Add enumerate() to DSLX stdlib

[joannabrozek]

This PR adds the 'enumerate()' function with the 'generics' attribute to DSLX stdlib, replacing the existing built-in implementation.

This change was created because we wanted to enable conversion 'enumerate()' to IR.

[joannabrozek]

This PR is marked as draft since after adding function with the 'generics' attribute to stdlib, the xls_dslx_fmt_test test started failing, so we're looking into it. We suspect that this test doesn't support GenericTypeAnnotation.

[joannabrozek]

This PR is marked as draft since after adding function with the 'generics' attribute to stdlib, the xls_dslx_fmt_test test started failing, so we're looking into it. We suspect that this test doesn't support GenericTypeAnnotation.

This issue has now been resolved, so this PR is ready for review.

[tmichalak]

@richmckeever PTAL

[joannabrozek]

I rebased on the current main branch and applied suggested changes.
If there's anything else I need to do, let me know.

[rw1nkler]

Do we need anything else here? @richmckeever

[joannabrozek]

@richmckeever, I've noticed that the CI failed on internal checks. Can you help me find which test case fails?
Regarding the ZSTD pipeline, I think it should start passing after merging this PR: #3931

[joannabrozek]

I've rebased changes onto the latest main, so fix for ZSTD pipeline from
#3931 is now included.

[kbieganski]

@richmckeever Can we get a hint as to what internal checks are failing on this?

[richmckeever]

I think what we are seeing internally is just more cases where we would have to replace enumerate() with std::enumerate(). It may be easiest if you could separate the parts that are removing the old builtin into a separate PR. Then we can commit this PR, change all internal stuff to use the new function, and then you commit the removal of the old function.

[joannabrozek]

@richmckeever, I split this PR into two:

• 1/2: Add enumerate() to DSLX stdlib #4021
• 2/2: Add enumerate() to DSLX stdlib #4022

Please let me know if there is anything else I can do for you.

[mikex-oss]

Closing in favor of #4021 and #4022.