[clang] [Clang] Do not perform integral promotion if operands of expression `x ? : y` have the same type (PR #108837)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

I too am very concerned about the lack of tests here, there are some disappearing conditions I cannot help but think are there for a good reason, and would like to see some study as to why those where there and when.

I'm also concerned about the constexpr support being 'FIXME', it seems that this should just 'work' unless something odd is happening.

https://github.com/llvm/llvm-project/pull/108837