[BUGFIX] Remove trailing slash from autoload information files

If an extension defines a classmap in ext_emconf.php or composer.json which points
to a file instead of a directory. The relative path calculation adds
a trailing slash to the file name, which breaks the class loading.

This trailing slash needs to be removed. As a bonus the obsolete trailing slash
is also removed from directories.

Resolves: #70234
Releases: master
Change-Id: Id54c2692e10b8ec3283a4e3447c289dc4319042c
Reviewed-on: http://review.typo3.org/43669


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>