[FEATURE] Display the bad class name in makeInstance

The class name provided to GeneralUtility::makeInstance must not
start with a backslash. To help track down the offending code parts,
makeInstance now includes the offending class name in the exception
message.

Resolves: #64665
Releases: master
Change-Id: I745840f9d6497b0b73bd2f1872310728e780ae5e
Reviewed-on: http://review.typo3.org/36472


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benjamin Mack <benni@typo3.org>
Tested-by: Benjamin Mack <benni@typo3.org>