GTest functional tests that include parameters and uORB messaging (#12521)

* Add kdevelop to gitignore

* Add test stubs

* Rename px4_add_gtest to px4_add_unit_gtest

* Add infrastructure to run functional tests

* Add example tests with parameters and uorb messages

* Fix memory issues in destructors in uORB manager and CDev

* Add a more real-world test of the collision prevention

src/modules/uORB/uORBDeviceMaster.cpp

@@ -102,10 +102,10 @@ uORB::DeviceMaster::advertise(const struct orb_metadata *meta, int *instance, in
 			return -ENOMEM;
 		}
 
-		/* construct the new node */
+		/* construct the new node, passing the ownership of path to it */
 		uORB::DeviceNode *node = new uORB::DeviceNode(meta, group_tries, devpath, priority);
 
-		/* if we didn't get a device, that's bad */
+		/* if we didn't get a device, that's bad, free the path too */
 		if (node == nullptr) {
 			free((void *)devpath);
 			return -ENOMEM;
@@ -133,9 +133,6 @@ uORB::DeviceMaster::advertise(const struct orb_metadata *meta, int *instance, in
 				}
 			}
 
-			/* also discard the name now */
-			free((void *)devpath);
-
 		} else {
 			// add to the node map;.
 			_node_list.add(node);