SERVER-8998 Register an atexit handler to call _exit if a library calls ::exit().

This prevents static destructors from running if the program exits via ::exit()
or by returning from main(), until such time as we fix normal exit behavior.
SERVER-9866 make ConfigServer::checkConfigServersConsistent check config.collections also
SERVER-11812 Remove query bounds test for now-invalid index
SERVER-11715 fix Array.tojson ugly output