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

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https://github.com/cor3ntin commented:

Sorry for the late review!
I think the change make sense but needs more tests. Thanks!

After we land that, could you spend some time trying to cleanup some of these functions?

- maybe pass an enum instead of a myriad of bool parameters
- maybe return a struct with the output parameters instead of just TemplateDeductionResult ?

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