Fail more informatively when tests are affected by syncback race condition.
Fail more informatively when tests are affected by syncback race condition.

If you have a syncback service running in the background and talking to the
test database, it will grab actions enqueued by the tests, causing the tests to
fail cryptically. Detect this case, and raise a more informative error.

EthanBlackburn/sync-engine,ErinCall/sync-engine,gale320/sync-engine,closeio/nylas,ErinCall/sync-engine,jobscore/sync-engine,wakermahmud/sync-engine,wakermahmud/sync-engine,PriviPK/privipk-sync-engine,nylas/sync-engine,Eagles2F/sync-engine,Eagles2F/sync-engine,EthanBlackburn/sync-engine,Eagles2F/sync-engine,PriviPK/privipk-sync-engine,Eagles2F/sync-engine,gale320/sync-engine,nylas/sync-engine,jobscore/sync-engine,wakermahmud/sync-engine,gale320/sync-engine,closeio/nylas,closeio/nylas,PriviPK/privipk-sync-engine,jobscore/sync-engine,PriviPK/privipk-sync-engine,nylas/sync-engine,Eagles2F/sync-engine,ErinCall/sync-engine,nylas/sync-engine,EthanBlackburn/sync-engine,ErinCall/sync-engine,PriviPK/privipk-sync-engine,gale320/sync-engine,closeio/nylas,EthanBlackburn/sync-engine,EthanBlackburn/sync-engine,wakermahmud/sync-engine,jobscore/sync-engine,gale320/sync-engine,ErinCall/sync-engine,wakermahmud/sync-engine