autotest: Add plane test for landing with barometer drift.

Tools/autotest/ArduPlane_Tests/Landing-Drift/ap-circuit.txt

@@ -0,0 +1,11 @@
+QGC WPL 110
+0	0	0	16	0.000000	0.000000	0.000000	0.000000	-35.363257	149.165237	584.099976	1
+1	0	3	22	15.000000	0.000000	0.000000	0.000000	0.000000	0.000000	80.000000	1
+2	0	3	19	600.000000	0.000000	1.000000	0.000000	-35.356752	149.164022	100.000000	1
+3	0	3	189	0.000000	0.000000	0.000000	0.000000	0.000000	0.000000	100.000000	1
+4	0	3	16	0.000000	0.000000	0.000000	0.000000	-35.360205	149.164455	100.430000	1
+5	0	3	16	0.000000	0.000000	0.000000	0.000000	-35.360629	149.160695	94.470001	1
+6	0	3	16	0.000000	0.000000	0.000000	0.000000	-35.368664	149.161993	83.139999	1
+7	0	3	16	0.000000	0.000000	0.000000	0.000000	-35.368122	149.166056	60.000000	1
+8	0	3	16	0.000000	0.000000	0.000000	0.000000	-35.366814	149.165878	50.000000	1
+9	0	3	21	0.000000	0.000000	0.000000	1.000000	-35.362911	149.165222	0.000000	1

Tools/autotest/arduplane.py

@@ -3048,6 +3048,26 @@ class AutoTestPlane(AutoTest):
         if ex is not None:
             raise ex
 
+    def fly_landing_baro_drift(self):
+
+        self.customise_SITL_commandline([], wipe=True)
+
+        self.set_parameters({
+            "SIM_BARO_DRIFT": -0.02,
+            "SIM_TERRAIN": 0,
+            "RNGFND_LANDING": 1,
+            "RNGFND1_MAX_CM": 4000,
+            "LAND_SLOPE_RCALC": 2,
+            "LAND_ABORT_DEG": 2,
+        })
+
+        self.reboot_sitl()
+
+        self.wait_ready_to_arm()
+        self.arm_vehicle()
+
+        self.fly_mission("ap-circuit.txt", mission_timeout=1200)
+
     def tests(self):
         '''return list of all tests'''
         ret = super(AutoTestPlane, self).tests()
@@ -3257,6 +3277,10 @@ class AutoTestPlane(AutoTest):
              "AHRS trim testing",
              self.ahrstrim),
 
+            ("Landing-Drift",
+             "Circuit with baro drift",
+             self.fly_landing_baro_drift),
+
             ("LogUpload",
              "Log upload",
              self.log_upload),