[OpenMPIRBuilder][Fix] Move llvm::omp::types to OpenMPIRBuilder.
D82193 exposed a problem with global type definitions in
OMPConstants.h. This causes a race when running in thinLTO mode.
Types now live inside of OpenMPIRBuilder to prevent this from happening.
Subscribers: yaxunl, hiraditya, guansong, dexonsmith, aaron.ballman, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D83176