The `Block_Supported_Styles_Test` class is not a `TestCase` to be extended, but an actual concrete test class. In order to run as expected, it should be placed under `phpunit/tests/blocks/` along with the other block tests.
Additionally:
* Add missing visibility keywords to test methods.
* Update the expected results to the currently used format for the tests to pass.
* Remove two outdated tests. The functionality being tested there is no longer available in this manner, so these tests are redundant.
Follow-up to [49226], [49310].
Props jrf, aristath, youknowriad.
See #53363.
git-svn-id: https://develop.svn.wordpress.org/trunk@51490 602fd350-edb4-49c9-b593-d223f7449a82