More assertive sanity check for process abs start time column
More assertive sanity check for process abs start time column

Summary: We fixed the meaning of `start_time` in previous PR/diffs, let's check it in the integration test.

Reviewed By: SAlexandru

Differential Revision: D13918628

fbshipit-source-id: 60f4ff74eadfbe286dfb325d713389f01142a0f8

hackgnar/osquery,hackgnar/osquery,hackgnar/osquery