[clang][cli] Add support for options with two flags for controlling the same field.

This enables automatically parsing and generating CC1 arguments for options where two flags control the same field, e.g. -fexperimental-new-pass-manager and -fno-experimental new pass manager.

Reviewed By: Bigcheese, dexonsmith

Original patch by Daniel Grumberg.

Differential Revision: https://reviews.llvm.org/D83071