[clang] [flang] [FLANG][Driver] Support -fno-profile-generate and -fprofile-generate=<dir> in flang (PR #216643)

[Tarun Prabhu via cfe-commits]

https://github.com/tarunprabhu approved this pull request.

A `TODO` comment in the code saying that we should consider reusing clang's approach may be helpful. We should avoid duplicating too much code before we refactor. If you plan to do the refactor relatively soon, such a comment might not be necessary.

https://github.com/llvm/llvm-project/pull/216643