Run scheduled report tests on any PHP version #18666

Description:

We have a couple of scheduled report tests that are only executed on certain systems:
https://github.com/matomo-org/matomo/blob/9fa38fe3cc31632e2a6a0e916c5df7185c872e0d/tests/PHPUnit/Framework/TestCase/SystemTestCase.php#L251-L273
https://github.com/matomo-org/matomo/blob/9fa38fe3cc31632e2a6a0e916c5df7185c872e0d/tests/PHPUnit/Framework/TestCase/SystemTestCase.php#L315-L396

If I remember correctly we had some issues when running those tests on PHP 5 and PHP 7, as the results differed back then.
It seems that isn't a problem anymore when running them on PHP 7 and PHP 8. At least there are no tests failing.
But based on the number of test cases it looks like they are executed.

refs #18499

This issue is in "needs review" but there has been no activity for 7 days. ping @matomo-org/core-reviewers