build: remove WORKSPACE from ci-builder calculation

[ParkMyCar]

I don't think anything in the WORKSPACE file should impact what gets included in the ci-builder image, and when we do include it, small changes like adding a new crate result in re-building the image.

@def- can you remember why we made this change? It wasn't immediately obvious to me from the original PR #30674.

Motivation

Less frequent rebuilds of the CI builder image.

Checklist

• This PR has adequate test coverage / QA involvement has been duly considered. (trigger-ci for additional test/nightly runs)
• This PR has an associated up-to-date design doc, is a design doc (template), or is sufficiently small to not require a design.
• If this PR evolves an existing $T ⇔ Proto$T mapping (possibly in a backwards-incompatible way), then it is tagged with a T-proto label.
• If this PR will require changes to cloud orchestration or tests, there is a companion cloud PR to account for those changes that is tagged with the release-blocker label (example).
• If this PR includes major user-facing behavior changes, I have pinged the relevant PM to schedule a changelog post.

[def-]

Changing the llvm toolchain, which is in that file, should require a ci-builder rebuild. Last time you updated that in WORKSPACE there were wrong hashes I believe, and we were still using the old image. Only when I changed something else in the ci-builder did it fail.

Is it possible to split WORKSPACE into two files, one which gets touched for new modules and/or any other changes in src/? Then we could exclude that file

[ParkMyCar]

Changing the llvm toolchain, which is in that file, should require a ci-builder rebuild. Last time you updated that in WORKSPACE there were wrong hashes I believe, and we were still using the old image. Only when I changed something else in the ci-builder did it fail.

The LLVM toolchain in WORKSPACE should only get used by Bazel, AFAIK the CI builder image uses a totally separate toolchain. Ideally the two would be linked, but the Bazel one still doesn't support sanitizers, I have gotten that 100% working yet.

Is it possible to split WORKSPACE into two files, one which gets touched for new modules and/or any other changes in src/? Then we could exclude that file

Unfortunately WORKSPACE is a Bazel concept and it can't be split :/