GDScript: Add check for super() methods not being implemented

modules/gdscript/tests/scripts/analyzer/features/virtual_method_implemented.gd

@@ -0,0 +1,21 @@
+class BaseClass:
+	func _get_property_list():
+		return {"property" : "definition"}
+
+class SuperClassMethodsRecognized extends BaseClass:
+	func _init():
+		# Recognizes super class methods.
+		var _x = _get_property_list()
+
+class SuperMethodsRecognized extends BaseClass:
+	func _get_property_list():
+		# Recognizes super method.
+		var result = super()
+		result["new"] = "new"
+		return result
+
+func test():
+	var test1 = SuperClassMethodsRecognized.new()
+	print(test1._get_property_list()) # Calls base class's method.
+	var test2 = SuperMethodsRecognized.new()
+	print(test2._get_property_list())