Analyse if we should start checking (4.4 and up) for setAccessible() reflection uses

[stronk7]

The setAccessible() methods are, since PHP 8.1 no-op. That implies that, since Moodle 4.4.0 (that requires PHP 8.1), there shouldn't be any use in core.

This issue is about to check if PHPCompatibility already has that and, depending on that, decide how we incorporate that check for us (importing if PHPCompatibility has it, implementing ir here, maybe as part of some deprecated processor, or just manually, we already have some similar sniffs looking for forbidden and other functions...)

Ciao :-)