[clang] [OpenMP 6.0 ]Codegen for Reduction over private variables with reduction clause (PR #134709)

[Alexey Bataev via cfe-commits]

alexey-bataev wrote:

Can you add a few runtime tests, some with UDR with classes, several reduction items with the different types, to check that functional part works correctly? You can add it to the libomp right in this patch. Just want to be sure we do not miss anything here

https://github.com/llvm/llvm-project/pull/134709