[clang] [Clang][OpenMP][OMPIRBuilder] Move Clang's OpenMP Member/MemberOf flag helpers into the OMPIRBuilder (PR #67844)

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shraiysh wrote:

> I'll see what I can do about adding an OpenMPIRBuilderTest.cpp to the patch.

I think it’s okay if it’s tested by clang tests (as Johannes mentioned). In case you decide to add tests for this, there is already an OpenMPIRBuilderTest.cpp in `llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp`. You can add one there if you’d like to. 

https://github.com/llvm/llvm-project/pull/67844