[clang] [llvm] [clang][OMPIRBuilder] Use default target AS to create types (PR #158152)

[Nick Sarnie via cfe-commits]

sarnex wrote:

Thanks Tom! In my case I'm never going through mlir yet, but it should work, so I will make a separate PR quickly after this to fix MLIR and add you as a reviewer.

https://github.com/llvm/llvm-project/pull/158152