[clang] [clang] Improve diagnostics for constraints of inline asm (NFC) (PR #96363)

[Matt Arsenault via cfe-commits]

https://github.com/arsenm commented:

It's really unfortunate to have to add all this asm handling to clang. Can't it rely on backend diagnostic remarks for this? 

https://github.com/llvm/llvm-project/pull/96363