[llvm] [MC] Avoid DWARF emission after inline asm errors (PR #228707)

[Fangrui Song via llvm-commits]

MaskRay wrote:

Thanks for looking into this. The root cause is that `AsmParser` errors reach `MCContext::diagnose` (via `AsmParser::DiagHandler`), which forwards them to the handler but, unlike `MCContext::reportError`, doesn't set `HadError`. Setting it there covers every inline asm parse error without a new `setHadError` API or the `NoFinalize` special case. Fixing in an alternative

https://github.com/llvm/llvm-project/pull/228707