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

[via llvm-commits]

koachan 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 https://github.com/llvm/llvm-project/issues/110956.

> 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 :)

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