Revoke coll/han subcomms when a comm is revoked (and general framework) #13420
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Without a way to revoke the subcomms created by the coll modules, processes can get stuck waiting on sub-operations of a collective on a revoked communicator.
I chose to put the top-level coll_revoke_local into the comm's c_coll object as a function pointer, but that's only to maintain the same programming pattern as the other functions. The top-level function is static, and calls coll_revoke_local on the comm for each of it's active modules.