[CLEANUP] Drop the compatibility class files "class.*"

Now that every extension should be using an autoloader,
we don't need these dummy files anymore.

Resolves: #50246

Change-Id: Id33d19cf4f971c4d2c3382822af11ccf86065e4e
Reviewed-on: http://review.typo3.org/35110
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>