This commit includes two changes. First, the locality code has been
factored out to improve readability and maintainability. Second,
instead of looking up each proc using ompi_group_peer_lookup the code
now uses ompi_group_peer_lookup_existing. The code falls back on modex
if a proc doesn't exist. This will prevent MPI_Comm_split_type from
allocating ompi_proc_t's for every process in the job.
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
c45789a222