[clang][cli] Squash multiple cc1 -fxxx-exceptions flags into single -exception-model=xxx option

This patch enables marshalling of the exception model options while enforcing their mutual exclusivity. The clang driver interface remains the same, this only affects the cc1 command line.

Depends on D93215.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D93216