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

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

By the way, just realized I should mention this, but we still support '-fno-relaxed-template-template-args', if anything, you could compile SPEC with that flag in order to workaround this breakage meanwhile, until the above patch is merged.

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