[clang] [clang] Enable C++17 relaxed template template argument matching by default (PR #89807)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

By the way, creduce/cvise won't help much here unless the interestingness test accounts for 'works on GCC'.

Otherwise, It'd be trivial to conjure some snippet of code that works before P0522, but breaks afterward as intended.

https://github.com/llvm/llvm-project/pull/89807