Tests

More precise `array_keys` return type #19459

Job	Run time
Tests (7.4, ubuntu-latest)	1m 7s
Tests (7.4, windows-latest)	1m 25s
Tests (8.0, ubuntu-latest)	1m 3s
Tests (8.0, windows-latest)	1m 25s
Tests (8.1, ubuntu-latest)	1m 5s
Tests (8.1, windows-latest)	1m 24s
Tests (8.2, ubuntu-latest)	59s
Tests (8.2, windows-latest)	1m 26s
Tests (8.3, ubuntu-latest)	41s
Integration tests (ubuntu-latest)	32s
Tests (8.3, windows-latest)	1m 28s
Determine levels tests matrix	40s
Integration tests (windows-latest)	1m 18s
Tests (8.4, ubuntu-latest)	49s
Tests (8.4, windows-latest)	1m 25s
Levels tests	1s
	16m 48s

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