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

[via cfe-commits]

cor3ntin wrote:

@mizvekov We have a bunch of related issues, could you look at them
https://github.com/llvm/llvm-project/issues?q=is%3Aissue+is%3Aopen+%22-frelaxed-template-template-args%22 ?

(and add tests + "Fixes #XXXX` to the commit message, as well as mentioning all the fixed issues in the release notes)

Thanks!

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