[llvm] [SystemZ] Remove incorrect areInlineCompatible hook (PR #152494)

[Ulrich Weigand via llvm-commits]

https://github.com/uweigand approved this pull request.

>However, the implementation that actually applies is the one in BasicTTIImpl.h, which performs a feature subset comparison. As such, this regressed inlining, most  concerningly of functions without +vector into functions with +vector.

Ah, I see.  In that case I agree that we should revert that change for now.

https://github.com/llvm/llvm-project/pull/152494