Tests: Rename some oEmbed test classes as per the naming conventions.

Includes moving the data provider after the corresponding test for consistency with the rest of the test suite.

Follow-up to [34903], [62223], [62224].

See #64225.

git-svn-id: https://develop.svn.wordpress.org/trunk@62227 602fd350-edb4-49c9-b593-d223f7449a82