[clang] Add option to avoid generating coverage mappings for unused functions (PR #92582)

[Justin Cady via cfe-commits]

justincady wrote:

@ZequanWu I tested your first suggestion (`-fprofile-list`) and I believe there's a bug preventing reduction of binary size. See https://github.com/llvm/llvm-project/issues/97588.

https://github.com/llvm/llvm-project/pull/92582