Chore: macosx unsupported for a performance file because inconsistent…

… RC (#6062)

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license](https://github.com/dafny-lang/dafny/blob/master/LICENSE.txt).</small>

Source/IntegrationTests/TestFiles/LitTests/LitTest/README.md

@@ -68,6 +68,14 @@ will be flagged by CI, and should be fixed by either converting it to use
 to flag it as intentionally inconsistent,
 for tests of backend-specific externs for example.
 
+If a platform is not supported, please use the following command:
+
+```
+// UNSUPPORTED: windows, macosx
+```
+
+You can specify one or multiple platforms separated by a comma among `windows`, `posix`, `macosx`
+
 ## Executing Tests from JetBrains Rider
 
 You will likely find it more convenient to run tests from an IDE such as

Source/IntegrationTests/TestFiles/LitTests/LitTest/dafny0/CoinductiveProofs.dfy

@@ -1,6 +1,6 @@
+// UNSUPPORTED: macosx
+// Unsupported because the resource count is slightly different on macosx
 // RUN: %testDafnyForEachResolver --expect-exit-code=4 "%s" -- --allow-deprecation --performance-stats=1
-
-
 codatatype Stream<T> = Cons(head: T, tail: Stream)
 
 ghost function Upward(n: int): Stream<int>