AbstractClassRestrictions: improve how anonymous classes are handled #1286

Job	Run time
PHPStan	15s
Find typos	5s
Ruleset test: PHP latest on PHPCS dev	26s
Ruleset test: PHP latest on PHPCS lowest	18s
Ruleset test: PHP latest on PHPCS stable	12s
XML Code style	1m 9s
Run code sniffs	39s
	3m 4s

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