Having two code paths for this is unreliable and can lead to bugs. Also, in some cases Apache isn't setting the PATH_INFO variable when mod_rewrite is used.
Fixes https://github.com/nextcloud/server/issues/983
* Move a-b to PSR-4
* Move c-d to PSR-4
* Move e+g to PSR-4
* Move h-l to PSR-4
* Move m-r to PSR-4
* Move s-u to PSR-4
* Move files/ to PSR-4
* Move remaining tests to PSR-4
* Remove Test\ from old autoloader