The tests are the most valuable part of the CI pipeline, so these should
be run first.
If a PHPCS or PHPStan error occurs but the tests pass, we know the
functionality works and the error can be addressed.
If a test fails, the CI pipeline will fail sooner.
In the future, the tasks could be split into separate jobs though it
would need to be done in a way that doesn't add a lot of repetition.
Refs: OD-41
Oliver Davies
17142d868f