PHPCS is run even when it cannot check any files

Problem/Motivation

The PHPCS job is added to the pipeline and runs even when there are no files for it to check.

Here is an example where there a no .php files or any other file extensions that PHPCS can check. Running with _PHPCS_EXTRA: -v shows 0 files checked.

Maybe there is a mismatch between the job rules and the list of php files we derive? It is odd to have the job running when it cannot do anything.

Proposed resolution