Revert Regression test

This reverts commit 1513b3b.

Author: ondrejmirtes

tests/PHPStan/Rules/Methods/OverridingMethodRuleTest.php

@@ -510,10 +510,4 @@ public function testParameterTypeWidening(int $phpVersionId, array $errors): voi
 		$this->analyse([__DIR__ . '/data/parameter-type-widening.php'], $errors);
 	}
 
-	public function testBug5589(): void
-	{
-		$this->phpVersionId = PHP_VERSION_ID;
-		$this->analyse([__DIR__ . '/data/bug-5589.php'], []);
-	}
-
 }