[clang] [clang] check deduction consistency when partial ordering function templates (PR #100692)

[Alexander Kornienko via cfe-commits]

alexfh wrote:

What about this case: https://godbolt.org/z/1TsK96ao8 ? It's a reduction of one of a large number of broken builds we see after this patch.

https://github.com/llvm/llvm-project/pull/100692