[clang] [AArch64][SME2] Fix SME2 mla/mls tests (PR #76711)

[Kerry McLaughlin via cfe-commits]

https://github.com/kmclaughlin-arm commented:

Thanks for updating this @MDevereau, I think there are just a few more tests that should be included in this PR.

https://github.com/llvm/llvm-project/pull/76711