resmoke.py logging output from data consistency hooks twice to logkeeper

The changes from SERVER-31556 made it so any logs written by resmoke.py hooks go to logkeeper's "global logs". This ensured that we wouldn't miss output from the hook when it logs a message either before or without starting a new test case. However, by changing the parent in the logging hierarchy of the logger used by the data consistency hooks, we've inadvertently changed resmoke.py to write the log output to logkeeper's "global logs" once and then again to logkeeper's "test logs" after starting the test case.

We should instead start the hook's test case with the TestsRootLogger instance as the parent.