[clang] [modulemap] Add -fno-implicit-module-map-file= to exclude from implicit discovery (PR #208191)

[Tor Arne Vestbø via cfe-commits]

torarnv wrote:

> You could instead pass a vfsoverlay that includes the modulemap and only pass that to swift clients.

With the goal being primarily Swift consumption, I think we want to keep the Swift path as golden as possible.

https://github.com/llvm/llvm-project/pull/208191