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

[via cfe-commits]

cor3ntin wrote:

I think that if we don't have a fix in the next 24-48 hours, and no clarity on the issue - a revert should be considered (note that I think it will be disruptive for llvm too as we are, I think, 3 patches deep, but i agree that keeping a regression on trunk for too long is undesirable)

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