[clang] [Clang] Emit TBAA info for enums in C (PR #73326)

[John McCall via cfe-commits]

rjmccall wrote:

This seems conservatively correct, yeah.  My reading is that we could also use the underlying type as a parent type for the TBAA metadata: enums are compatible with their underlying type, but two enums with the same underlying type are not compatible with each other.  But this rule should also work.

https://github.com/llvm/llvm-project/pull/73326