autotest: stop taking off when we're already in the air

Depending on timing we can miss the fact we're already at altitude as we
take off in stabilize and manipulate the throttle before checking
altitude

Tools/autotest/arducopter.py

@@ -656,7 +656,7 @@ def fly_throttle_failsafe(self, side=60, timeout=360):
         num_wp = self.load_mission("copter_mission.txt")
         if not num_wp:
             raise NotAchievedException("load copter_mission failed")
-        self.takeoffAndMoveAway()
+#        self.takeoffAndMoveAway()
         self.change_mode("AUTO")
         self.set_parameter("SIM_RC_FAIL", 1)
         self.delay_sim_time(5)