[llvm] [X86InstrInfo] support memfold on spillable inline asm (PR #70832)

[Nick Desaulniers via llvm-commits]

nickdesaulniers wrote:

Note to reviewers: this is a stacked commit which depends on:
1. https://github.com/llvm/llvm-project/pull/70738
2. https://github.com/llvm/llvm-project/pull/70743
3. https://github.com/llvm/llvm-project/pull/70747
4. https://github.com/llvm/llvm-project/pull/70747

https://github.com/llvm/llvm-project/pull/70832