[BUGFIX] Fix minor error handler code bugs

ErrorHandler has a few minor quirks:

1. the protected property is an integer (bitwise-comparison) but initialized as array
2. small indention and repeatable string introduction
3. human-readable text for E_USER_DEPRECATED missing
4. error handling when no autoloader is available is obsolete.

The patch fixes all these minor issues.

Resolves: #82375
Releases: master, 8.7
Change-Id: Id6f9616602021e04ac6a50737438253a62da788c
Reviewed-on: https://review.typo3.org/54002


Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Helmut Hummel <typo3@helhum.io>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>