autotest: fix arming checks test

waity for accels/gyros to settle

Tools/autotest/arducopter.py

@@ -6444,6 +6444,7 @@ class AutoTestCopter(AutoTest):
             "EK3_SRC1_VELXY": 0,
         })
         self.reboot_sitl()
+        self.delay_sim_time(30)  # wait for accels/gyros to settle
 
         # check for expected EKF flags
         ahrs_ekf_type = self.get_parameter("AHRS_EKF_TYPE")

Tools/autotest/common.py

@@ -9340,6 +9340,7 @@ Also, ignores heartbeats not from our target system'''
     def ArmFeatures(self):
         '''Arm features'''
         # TEST ARMING/DISARM
+        self.delay_sim_time(12)  # wait for gyros/accels to be happy
         if self.get_parameter("ARMING_CHECK") != 1.0 and not self.is_sub():
             raise ValueError("Arming check should be 1")
         if not self.is_sub() and not self.is_tracker():