Remove 'UnitTestList' hook

No longer needed now that extension unittests are autodiscovered.

Bug: T142120
Bug: T142121
Change-Id: I89cfc1ea3e652ebec1cd67f62810586c4ef49574

GadgetHooks.php

@@ -302,17 +302,6 @@ class GadgetHooks {
 		return true;
 	}
 
-	/**
-	 * UnitTestsList hook handler
-	 * @param array $files
-	 * @return bool
-	 */
-	public static function onUnitTestsList( array &$files ) {
-		$testDir = __DIR__ . '/tests/';
-		$files = array_merge( $files, glob( "$testDir/*Test.php" ) );
-		return true;
-	}
-
 	/**
 	 * Add the GadgetUsage special page to the list of QueryPages.
 	 * @param array &$queryPages

extension.json

@@ -103,9 +103,6 @@
 		"ResourceLoaderRegisterModules": [
 			"GadgetHooks::registerModules"
 		],
-		"UnitTestsList": [
-			"GadgetHooks::onUnitTestsList"
-		],
 		"wgQueryPages": [
 			"GadgetHooks::onwgQueryPages"
 		]