[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]

davemgreen wrote:

Thanks for doing this, it sounds like the right place to change to me. Could you add the test case from #123029?

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