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

[CHANDRA GHALE via cfe-commits]

chandraghale wrote:

Refactored code to look up the expression and handle UDR, emitting it as is.  updated the lit test.

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