[llvm] [SPARC] Allow overaligned `alloca`s (PR #107223)

[Rainer Orth via llvm-commits]

rorth wrote:

> > That said, I'm fine with merging the patch now, with one caveat: please first file an Issue for the remaining failure with everything that's known about the issue
> 
> Posted the issue tracker at #110956.

Fine, thanks.

> > then `XFAIL` the testcase on SPARC to avoid the Solaris/sparcv9 bot turning red immediately (oh wait, it already is due to PR #106951 ;-().
> 
> The buildbot should be green again now :)

It is indeed.  I wonder what to do about the testcase now.  I guess there are 3 options:
- `XFAIL` it on SPARC, referencing the Issue.
- Mark the test `UNSUPPORTED` everywhere.
- Remove it wholesale.

https://github.com/llvm/llvm-project/pull/107223