Find ways to reduce the need for NodeJS

[Crixu]

Right now the phpunit-test-runner requires node and npm in order to build the artifacts to run the tests. We rely on the grunt file from the wordpress-develop repo but the actual phpunit tests we run don't require any of those artifacts.

Describe the solution you'd like
We should spent some research time to see if we can omit the build process as the phpunit-tests don't require all the artifacts to successfully perform all tests.

Additional context
This was part of the research for #243 as a lot of hosts complained about the extra steps included to have a node environment ready to do all this including the additional time needed.

[ramonfincken]

As discussed , I have rewritten my code to be generic and used this PR : #246

[desrosj]

I had a thought today when looking through open issues again.

In WordPress Core, the workflow responsible for testing the build process uploads a ZIP file of the build directory after running the build process as an artifact. That artifact is retained for 90 days.

The artifact includes the commit SHA value in the name. Perhaps we could update the runner to make use of these artifacts by:

• searching for the corresponding artifact
• downloading the ZIP
• unzipping

The one downfall of this approach is that it does require the workflow to succeed. When it does not, there would need to be a fallback mechanism.

[ramonfincken]

A fallback is a good idea