Tests using yield*, also to test codepath via .throw()

This includes the test case mentioned in ecma262 issue comment:
tc39/ecma262#1849 (comment)

Also using yield* we can test the changes to AsyncFromSyncIteratorContinuation
when called via .throw().

test/built-ins/AsyncFromSyncIteratorPrototype/next/yield-iterator-next-rejected-promise-close.js

@@ -0,0 +1,62 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-%asyncfromsynciteratorprototype%.next
+description: next() will reject promise if resolving result promise abrupt completes.
+info: |
+  %AsyncFromSyncIteratorPrototype%.next ( value )
+  ...
+  3. Let promiseCapability be ! NewPromiseCapability(%Promise%).
+  4. Let syncIteratorRecord be O.[[SyncIteratorRecord]].
+  5. If value is present, then
+    ...
+  6. Else,
+    a. Let result be IteratorNext(syncIteratorRecord).
+  7. IfAbruptRejectPromise(result, promiseCapability).
+  8. Return ! AsyncFromSyncIteratorContinuation(result, promiseCapability, syncIteratorRecord, true).
+
+  AsyncFromSyncIteratorContinuation ( result, promiseCapability, syncIteratorRecord, closeOnRejection )
+  1. Let done be IteratorComplete(result).
+  2. IfAbruptRejectPromise(done, promiseCapability).
+  3. Let value be IteratorValue(result).
+  4. IfAbruptRejectPromise(value, promiseCapability).
+  5. Let valueWrapper be PromiseResolve(%Promise%, value).
+  6. If valueWrapper is an abrupt completion, done is false, and closeOnRejection is true, then
+    a. Set valueWrapper to IteratorClose(syncIteratorRecord, valueWrapper).
+  ...
+  12. If done is true, or if closeOnRejection is false, then
+    ...
+  13. Else,
+    a. Let closeIterator be a new Abstract Closure with parameters (error) that captures syncIteratorRecord and performs the following steps when called:
+        i. Return ? IteratorClose(syncIteratorRecord, ThrowCompletion(error)).
+    b. Let onRejected be CreateBuiltinFunction(closeIterator, 1, "", « »).
+    c. NOTE: onRejected is used to close the Iterator when the "value" property of an IteratorResult object it yields is a rejected promise.
+  14. Perform PerformPromiseThen(valueWrapper, onFulfilled, onRejected, promiseCapability).
+  15. Return promiseCapability.[[Promise]].
+
+
+flags: [async]
+features: [async-iteration]
+includes: [asyncHelpers.js]
+---*/
+
+var finallyCount = 0;
+function Reject() {}
+
+function* iterator() {
+  try {
+    yield Promise.reject(new Reject());
+  } finally {
+    finallyCount += 1;
+  }
+}
+
+async function* asyncIterator() {
+  yield* iterator()
+}
+
+asyncTest(async () => {
+  await assert.throwsAsync(Reject, async () => asyncIterator().next(), "Promise should be rejected");
+  assert.sameValue(finallyCount, 1);
+});

test/built-ins/AsyncFromSyncIteratorPrototype/next/yield-next-rejected-promise-close.js

@@ -0,0 +1,67 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-%asyncfromsynciteratorprototype%.next
+description: next() will reject promise if resolving result promise abrupt completes.
+info: |
+  %AsyncFromSyncIteratorPrototype%.next ( value )
+  ...
+  3. Let promiseCapability be ! NewPromiseCapability(%Promise%).
+  4. Let syncIteratorRecord be O.[[SyncIteratorRecord]].
+  5. If value is present, then
+    ...
+  6. Else,
+    a. Let result be IteratorNext(syncIteratorRecord).
+  7. IfAbruptRejectPromise(result, promiseCapability).
+  8. Return ! AsyncFromSyncIteratorContinuation(result, promiseCapability, syncIteratorRecord, true).
+
+  AsyncFromSyncIteratorContinuation ( result, promiseCapability, syncIteratorRecord, closeOnRejection )
+  1. Let done be IteratorComplete(result).
+  2. IfAbruptRejectPromise(done, promiseCapability).
+  3. Let value be IteratorValue(result).
+  4. IfAbruptRejectPromise(value, promiseCapability).
+  5. Let valueWrapper be PromiseResolve(%Promise%, value).
+  6. If valueWrapper is an abrupt completion, done is false, and closeOnRejection is true, then
+    a. Set valueWrapper to IteratorClose(syncIteratorRecord, valueWrapper).
+  ...
+  12. If done is true, or if closeOnRejection is false, then
+    ...
+  13. Else,
+    a. Let closeIterator be a new Abstract Closure with parameters (error) that captures syncIteratorRecord and performs the following steps when called:
+        i. Return ? IteratorClose(syncIteratorRecord, ThrowCompletion(error)).
+    b. Let onRejected be CreateBuiltinFunction(closeIterator, 1, "", « »).
+    c. NOTE: onRejected is used to close the Iterator when the "value" property of an IteratorResult object it yields is a rejected promise.
+  14. Perform PerformPromiseThen(valueWrapper, onFulfilled, onRejected, promiseCapability).
+  15. Return promiseCapability.[[Promise]].
+
+
+flags: [async]
+features: [async-iteration]
+includes: [asyncHelpers.js]
+---*/
+
+var returnCount = 0;
+function Reject() {}
+
+const syncIterator = {
+  [Symbol.iterator]() {
+    return {
+      next() {
+        return { value: Promise.reject(new Reject()), done: false };
+      },
+      return() {
+        returnCount += 1;
+      }
+    };
+  }
+}
+
+async function* asyncIterator() {
+  yield* syncIterator;
+}
+
+asyncTest(async () => {
+  await assert.throwsAsync(Reject, async () => asyncIterator().next(), "Promise should be rejected");
+  assert.sameValue(returnCount, 1);
+});

test/built-ins/AsyncFromSyncIteratorPrototype/throw/iterator-result-rejected-promise-close.js

@@ -0,0 +1,83 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-%asyncfromsynciteratorprototype%.throw
+description: throw() will reject promise if resolving result promise abrupt completes.
+info: |
+  %AsyncFromSyncIteratorPrototype%.throw ( value )
+  ...
+  3. Let promiseCapability be ! NewPromiseCapability(%Promise%).
+  4. Let syncIteratorRecord be O.[[SyncIteratorRecord]].
+  5. Let syncIterator be syncIteratorRecord.[[Iterator]].
+  6. Let throw be GetMethod(syncIterator, "throw").
+  ...
+  9. If value is present, then
+    ...
+  10. Else,
+    a. Let result be Call(throw,syncIterator).
+  ...
+  13. Return ! AsyncFromSyncIteratorContinuation(result, promiseCapability, syncIteratorRecord, true).
+
+  AsyncFromSyncIteratorContinuation ( result, promiseCapability, syncIteratorRecord, closeOnRejection )
+  1. Let done be IteratorComplete(result).
+  2. IfAbruptRejectPromise(done, promiseCapability).
+  3. Let value be IteratorValue(result).
+  4. IfAbruptRejectPromise(value, promiseCapability).
+  5. Let valueWrapper be PromiseResolve(%Promise%, value).
+  6. If valueWrapper is an abrupt completion, done is false, and closeOnRejection is true, then
+    a. Set valueWrapper to IteratorClose(syncIteratorRecord, valueWrapper).
+  ...
+  12. If done is true, or if closeOnRejection is false, then
+    ...
+  13. Else,
+    a. Let closeIterator be a new Abstract Closure with parameters (error) that captures syncIteratorRecord and performs the following steps when called:
+        i. Return ? IteratorClose(syncIteratorRecord, ThrowCompletion(error)).
+    b. Let onRejected be CreateBuiltinFunction(closeIterator, 1, "", « »).
+    c. NOTE: onRejected is used to close the Iterator when the "value" property of an IteratorResult object it yields is a rejected promise.
+  14. Perform PerformPromiseThen(valueWrapper, onFulfilled, onRejected, promiseCapability).
+  15. Return promiseCapability.[[Promise]].
+
+flags: [async]
+features: [async-iteration]
+includes: [asyncHelpers.js]
+---*/
+
+var returnCount = 0;
+function Reject() {}
+
+var obj = {
+  [Symbol.iterator]() {
+    return {
+      next() {
+        return { value: 1, done: false };
+      },
+      throw() {
+        return {
+          value: Promise.reject(new Reject()),
+          done: false
+        };
+      },
+      return() {
+        returnCount += 1;
+      }
+    };
+  }
+};
+
+async function* asyncg() {
+  return yield* obj;
+}
+
+let iter = asyncg();
+
+asyncTest(async function () {
+  await assert.throwsAsync(Reject, async () => {
+    await iter.next();
+    return iter.throw();
+  }, "Promise should be rejected");
+  assert.sameValue(returnCount, 1);
+  const result = await iter.next();
+  assert(result.done, "the iterator is completed");
+  assert.sameValue(result.value, undefined, "value is undefined");
+})