Merge pull request #13750 from owncloud/enhanced-code-checker

3rdparty

core/command/app/checkcode.php

core/register_command.php

lib/private/app/codechecker.php

lib/private/app/codecheckvisitor.php

lib/private/installer.php

tests/data/app/code-checker/test-const.php

tests/data/app/code-checker/test-extends.php

tests/data/app/code-checker/test-implements.php

tests/data/app/code-checker/test-new.php

tests/data/app/code-checker/test-static-call.php

tests/lib/app/codechecker.php