Remove optional_*_flag fields from crosstool

They are not used anyway. optional_compiler_flag will be removed once internal
migration is finished.

RELNOTES: CppRules: Remove optional_*_flag fields from CROSSTOOL, they are not
used, and could be expressed using features.
PiperOrigin-RevId: 190600731
1 file changed
tree: 8b3f6ae704f1385ccfdeb2ca85cc14f10b146a43
  1. third_party/