Problems with ESMF managed threading in CESM

In CESM, ESMF_AWARE_THREADING (ESMF's managed threading) results in hangs because of issues with how PEs that are threads are treated like full PETs in CMEPS & NUOPC at the moment, but they can't do things like query the component VM. Also, connectors built on PE lists (vs PET lists) would hang during RouteHandle creation.

Start by reproducing the hang with ESMF_AWARE_THREADING enabled in CESM, then trace how CMEPS and NUOPC treat thread PEs versus PETs and how PE-list connectors create RouteHandles. Done means managed threading no longer hangs, component VM queries work for threaded PEs, and PE-list connector creation completes.

Written by the indexing model from the issue text.