[flang] [llvm] [OpenMP][Flang] Fix atomic operations on complex types (PR #165366)

[Kiran Chandramohan via llvm-commits]

kiranchandramohan wrote:

If the fix is in OpenMPIRBuilder, it is probably best to have the test also close to it.
llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp
mlir/test/Target/LLVMIR/openmp-llvm.mlir

https://github.com/llvm/llvm-project/pull/165366