MAGETWO-34952: Final cleanup to ensure Core module is properly removed

- Enable the Core module in the functional tests

Author: Bryant Luk

dev/tests/functional/phpunit.xml.dist

@@ -36,7 +36,7 @@
         <env name="testsuite_rule_path" value="Magento/Mtf/TestSuite/InjectableTests" />
         <env name="log_directory" value="var/log" />
         <env name="events_preset" value="base" />
-        <env name="module_whitelist" value="Magento_Install" />
+        <env name="module_whitelist" value="Magento_Install,Magento_Core" />
         <env name="report_file_name" value="test-cases-report.xml"/>
         <env name="basedir" value="var/log" />
         <env name="credentials_file_path" value="./credentials.xml.dist" />