[OpenMP] Implement 'omp_alloc' on the device (#102526)

Summary:
The 'omp_alloc' function should be callable from a target region. This
patch implemets it by simply calling `malloc` for every non-default
trait value allocator. All the special access modifiers are
unimplemented and return null. The null allocator returns null as the
spec states it should not be usable from the target.
GitOrigin-RevId: 74d23f15b6867898892f851db40a25f62dad4397
1 file changed