[llvm] [AArch64] Return early rather than asserting when Size of value passed to targetShrinkDemandedConstant is not 32 or 64 (PR #123084)

[David Green via llvm-commits]

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

Thanks, I have some nitpicks over cleaning up the test a little, but otherwise LGTM.

https://github.com/llvm/llvm-project/pull/123084