[llvm] [clang] [coverage] skipping code coverage for 'if constexpr' and 'if consteval' [WIP] (PR #78033)

[Hana Dusíková via cfe-commits]

hanickadot wrote:

I kept the whitespace in front of `if constexpr` and `if consteval` marked as uncovered in case whole region containing the ifs is uncovered. It's an esthetic thing and I will do it with a next patch to limit scope of this one.

https://github.com/llvm/llvm-project/pull/78033