Pass a "d7" parameter into scripts/test-only.sh and discard scripts/test-only-d7.sh

I've made the change to use test-only.sh for both D10 and D7.

The test-only jobs in these pipeline end green because there are no real changes, just commenting, to demonstrate the reverts

Testing in D10 via Scheduler MR253
concurrent=1 to use run-tests.sh
https://git.drupalcode.org/project/scheduler/-/pipelines/580863
concurrent=0 to use phpunit binary
https://git.drupalcode.org/project/scheduler/-/pipelines/580884

Testing in D7 via Scheduler MR252
Pipeline https://git.drupalcode.org/project/scheduler/-/pipelines/580369

There are also a few syntax changes, needed to allow me to run the script in a local terminal window. I was getting errors in some conditionals scripts/test-only.sh:84: = not found but replacing single [ ] with double [[ ]] fixed this. I don't know why some single [ ] are still OK and do not cause an error. I think it must be due to the type of the check. "[[ $VAR" == "0" ]] always needs doubles, whereas [ "$VAR != "" ] is OK with singles. It still works the same in the pipelines, so I thinks it's an OK change.

There are some temporary changes, and debug, but this is ready for review.

The changes look good, but I left some really minor feedback on the MR.

Thanks for the feedback, I agree with your suggestions and have made them.

Re-tested for D10 on Scheduler MR253
Using _PHPUNIT_CONCURRENT:1 to run run-tests.sh
https://git.drupalcode.org/project/scheduler/-/jobs/6394117#L487

D10 using _PHPUNIT_CONCURRENT:0 to run phpunit binary
https://git.drupalcode.org/project/scheduler/-/jobs/6393579#L487

Tested D7 via Scheduler MR252
This also checks deleting a newly added file
https://git.drupalcode.org/project/scheduler/-/jobs/6394208#L455

The temporary code was not actually needed here, as all testing is in other real MRs not downstream (yet), so I have removed that, and this is now ready for review again.

The code looks good and the tests look good too. I only made a text change suggestion on the MR for some of the initial echos.

RTBC pending that.

Thanks, yes they are good and I have applied those suggestions.

When this is committed I will merge it into ✨ Allow users to specify custom files that Test-only changes Active then continue on that.

This is merged now. Thanks.