[CLANG][PATCH][FPEnv] Add support for option -ffp-eval-method and extend...

[CLANG][PATCH][FPEnv] Add support for option -ffp-eval-method and extend #pragma float_control similarly

Need to update a clang regression test for VE after
https://reviews.llvm.org/D93769.

Reviewed By: simoll

Differential Revision: https://reviews.llvm.org/D108069