Fully migrate ContentCacheFlusherTest to behat

[mhsdesign]

There is this functional test leftover

neos-development-collection/Neos.Neos/Tests/Functional/Fusion/Cache/ContentCacheFlusherTest.php

Line 25 in ee36cc2

class ContentCacheFlusherTest extends FunctionalTestCase

which has been migrated partially with #4788 but as @dlubitz pointed out

I'd say I didn't test the workspace chains.

so that should ideally be added to the new behat tests

[dlubitz]

I think we can safely close this, as we improved the testing of the content cache flusher at all. And this specific case was just testing some implementation detail.

[mhsdesign]

Thank uuuuu ❤️