1) Fixed cognitive complexity issues reported by SonarQube.

2) Fixed code smell 'Add a nested comment explaining why this method is
   empty, or complete the implementation'.

web/regression/feature_utils/base_feature_test.py

@@ -48,12 +48,15 @@ class BaseFeatureTest(BaseTestGenerator):
             raise
 
     def runTest(self):
+        # To be implemented by child classes
         pass
 
     def before(self):
+        # To be implemented by child classes
         pass
 
     def after(self):
+        # To be implemented by child classes
         pass
 
     def tearDown(self):

web/regression/python_test_utils/sql_template_test_base.py

@@ -28,12 +28,15 @@ class SQLTemplateTestBase(BaseTestGenerator):
         self.database_name = -1
 
     def test_setup(self, connection, cursor):
+        # To be implemented by child classes
         pass
 
     def generate_sql(self, version):
+        # To be implemented by child classes
         pass
 
     def assertions(self, fetch_result, descriptions):
+        # To be implemented by child classes
         pass
 
     def runTest(self):

web/regression/runtests.py

@@ -410,6 +410,7 @@ class StreamToLogger(object):
             self.logger.log(self.log_level, line.rstrip())
 
     def flush(self):
+        # Function required to be implemented for logger
         pass