[OpenMP] Add GOMP 5.0 version symbols to API

* Add GOMP versioned pause functions
* Add GOMP versioned affinity format functions

To do the affinity format functions, only attach versioned symbols
to the APPEND Fortran entries (e.g., omp_set_affinity_format_) since
GOMP only exports two symbols (one for Fortran, one for C). Our
affinity format functions have three symbols.
e.g., with omp_set_affinity_format:
1) omp_set_affinity_format (Fortran interface)
2) omp_set_affinity_format_ (Fortran interface)
3) ompc_set_affinity_format (C interface)

Have the GOMP version of the C symbol alias the ompc_* 3) version
instead of the Fortran unappended version 1).

Differential Revision: https://reviews.llvm.org/D103647