Revert "[BUGFIX] Implement locking in ClassLoader"

This reverts commit 76284d26

The implemented locking is fine, but currently breaks a fresh new
installation (when there is no typo3temp directory yet). We remove
this feature for the release of beta7 and merge it afterwards again
to be able to improve upon it during the next week before the release
candidate.

Change-Id: Ie69352e5c7e3a224b0a0c71457efe3dbb8d90aac
Reviewed-on: https://review.typo3.org/28426
Reviewed-by: Ernesto Baschny
Tested-by: Ernesto Baschny