[clang] Fixes and closes #53952. Setting the ASTHasCompilerErrors member variable correctly based on the PP diagnostics. (PR #68127)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

There was a mix-up. I landed the original changes, @kazutakahirata saw what appeared to be a linker error after pulling those changes down and did a revert, but that turned out to be an issue local to their machine so I've reverted the revert (re-landing the original changes). So the code should be in now and should hopefully stay in,.

https://github.com/llvm/llvm-project/pull/68127