[clang] [flang] [flang][OpenMP] Add -f[no]-openmp-simd (PR #150269)

[Tom Eccles via cfe-commits]

https://github.com/tblah approved this pull request.

Looks great to me.

Just to elaborate on the need to keep the MLIR pass: the logic for which clauses apply to which directive in a compound construct is non-trivial. We thought it is better not to try to re-implement that here.

https://github.com/llvm/llvm-project/pull/150269