Fix for KMP_AFFINITY=respect with multiple processor groups

An assert() was being tripped when KMP_AFFINITY=respect + Multiple Processor
Groups. Let __kmp_affinity_create_proc_group_map() function be able to create
address2os object which contains a single group by deleting restriction that
process affinity mask must span multiple groups.


git-svn-id: https://llvm.org/svn/llvm-project/openmp/trunk@303101 91177308-0d34-0410-b5e6-96231b3b80d8