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

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phyBrackets wrote:

Not sure but the issue in the reverted commit seems like a backporting issue, so you may need to backport the changes in case. But I'd say wait for Aaron comment. 

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