[clang] [Clang] fix crash in codegen caused by deferred asm diagnostics under -fopenmp (PR #147163)

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

I haven't really thought about what the right strategy is for diagnostics here, specifically, but it looks like the OpenMP diagnostic suppression isn't working correctly.  If there's an error in a function, that should stop CodeGen from seeing the function at all.  If it's crashing, that means we're doing codegen on invalid functions, which we don't want to do.

https://github.com/llvm/llvm-project/pull/147163