No errors from GeneralUtility::callUserFunction without explicit request
Currently trying to call a method of a non existing (not autoloadable) class via `GeneralUtility::callUserFunction()` basically swallows the error (calls
debug() in fact) unless the
$errorMode parameter was explicitly set to
This happens basically nowhere in the core thus errors like these are hard to catch/find without additional effort.
$errorMode parameter should be dropped and the exception could be thrown based on @$TYPO3_CONF_VARS['SYS']['displayErrors'] instead. Always throwing an exception for these kind of errors would be preferable though.