[clang][cli] Expose -fno-cxx-modules in cc1

For some use-cases, it might be useful to be able to turn off modules for C++ in `-cc1`. (The feature is implied by `-std=C++20`.)

This patch exposes the `-fno-cxx-modules` option in `-cc1`.

Reviewed By: arphaman

Differential Revision: https://reviews.llvm.org/D106864