Tests

De-duplicate phpstan.php errors #23779

Job	Run time
Integration tests (ubuntu-latest)	5s
Integration tests (windows-latest)	1s
Tests (8.4, ubuntu-latest)	5s
Tests (8.3, ubuntu-latest)	5s
Tests (8.2, windows-latest)	7s
Tests (8.3, windows-latest)	10s
Tests (8.5, ubuntu-latest)	5s
Tests (8.2, ubuntu-latest)	5s
Tests (8.5, windows-latest)	9s
Tests (8.4, windows-latest)	4s
Determine levels tests matrix	4s
Tests with old PHPUnit (7.4, ubuntu-latest)	1s
Tests with old PHPUnit (8.0, windows-latest)	8s
Tests with old PHPUnit (7.4, windows-latest)	14s
Tests with old PHPUnit (8.1, windows-latest)	13s
Tests with old PHPUnit (8.0, ubuntu-latest)	5s
Tests with old PHPUnit (8.1, ubuntu-latest)	2s
Levels tests	1s
Mutation Testing	1s
	1m 45s

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