[OpenMP][OMPT] Fix locking testcases for 32 bit architectures
https://reviews.llvm.org/D58454 did not fix the problem for a typical use
case of building LLVM with gcc or icc and then testing with the newly built
The compilers do not agree on how to extend a 32-bit pointer to uint64, so
make the pointer unsigned first, before adjusting the size.
Patch by Joachim Protze
Differential Revision: https://reviews.llvm.org/D58506