[flang-commits] [flang] [flang] Use precompiled parsing headers (PR #130600)

[Tom Eccles via flang-commits]

tblah wrote:

@kparzysz are you happy to proceed [with the `#include`s not removed](https://github.com/llvm/llvm-project/pull/130600/commits/f9662a4eea7749b6e58ffbc085ea630ff9ab6b39) or would you still prefer not to see this change?

https://github.com/llvm/llvm-project/pull/130600