Revert "TEMP: no caching in abdt_conduit"

This reverts commit b4bb31195bfb850837ed2f282351e04824809856.
TEMP: log all conduit calls
arcyd-tester: refactor, extract 'setup_arcyds()'

Test Plan:
$ ./precommit.sh
$ ./proto/arcyd-tester
WIP: split out _happy_path
WIP: use multiprocessing.Pool instead of _WorkerManager
Revert "WIP: use multiprocessing.Pool instead of _WorkerManager"

This reverts commit 5ef3d36070f784231e5fed1a242dd2c17226dd1c.
fixup! abdi_processrepoarglist: merge worker review cache
WIP: abdi_processrepoarglist: remember _is_disabled