Add a test to make sure that accounts with sync_should_run set to False aren't started.
Add a test to make sure that accounts with sync_should_run set to False aren't started.

nylas/sync-engine,closeio/nylas,jobscore/sync-engine,nylas/sync-engine,closeio/nylas,nylas/sync-engine,jobscore/sync-engine,closeio/nylas,jobscore/sync-engine,closeio/nylas,nylas/sync-engine,jobscore/sync-engine