[llvm] Allow specifying libcxx builder image. (PR #110303)

[Michael Buch via llvm-commits]

Michael137 wrote:

> > > It looks like it's still failing with the latest run :-(
> > 
> > 
> > Argh that's unfortunate. How about we skip this test in libc++ CI to unblock this PR and I'll open a github issue to re-enable the test?
> > @EricWF It's probably easiest if you just add `--filter-out=TestDAP_subtleFrames.py` to the following LIT invocation as part of this PR:
> > https://github.com/llvm/llvm-project/blob/8c4bc1e75de27adfbaead34b895b0efbaf17bd02/libcxx/utils/ci/run-buildbot#L397
> > 
> > But if you prefer me doing it separately, let me know.
> 
> I have concerns about using the `run-buildbot` file to hide failing tests. I'll hold off on this change a little longer.

That's fair. In that case, @walter-erquinigo @clayborg Do you have any ideas on how to best debug this?

Summary: the `TestDAP_subtleFrames.py` test is failing when run in a container (in a container):
```
AssertionError: False is not true : launch failed (Cannot launch '/__w/.../lldb-dap/stackTrace/subtleFrames/TestDAP_subtleFrames.test_subtleFrames/a.out': personality set failed: Operation not permitted)
```

Our theory was that this happened when trying to disable ASLR. So we're no longer doing that for the DAP tests. But we're still failing with the above.

I'll try raise a draft PR that mimics this but with some additional LLDB logging.

https://github.com/llvm/llvm-project/pull/110303