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

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

The fix was committed, and we just reverted the revert, so default is back to `-frelaxed-template-template-args`.

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