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

[David Truby via cfe-commits]

DavidTruby wrote:

For what it's worth, MSVC and icc/icx also build @jeanPerier's example without complaint, so I think it should probably be accepted by clang as well even if it is ambiguous per the standard.

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