Remove broken compatibility hack for the legacy SkinTemplateToolboxEnd hook

SkinTemplateToolboxEnd hook really shouldn't be used and extensions should have been using BaseTemplateToolbox hook instead, for that hook's been around since MW 1.18.

Also this code was broken because $boxes was undefined.

Change-Id: I34537e8eb6ec0109253b5470d12d12d86c4dada0

includes/TimelessTemplate.php

@@ -160,25 +160,6 @@ class TimelessTemplate extends BaseTemplate {
 			$msgString = htmlspecialchars( $msg );
 		}
 
-		// HACK: Compatibility with extensions still using SkinTemplateToolboxEnd
-		$hookContents = '';
-		if ( $name == 'tb' ) {
-			if ( isset( $boxes['TOOLBOX'] ) ) {
-				ob_start();
-				// We pass an extra 'true' at the end so extensions using BaseTemplateToolbox
-				// can abort and avoid outputting double toolbox links
-				// Avoid PHP 7.1 warning from passing $this by reference
-				$template = $this;
-				Hooks::run( 'SkinTemplateToolboxEnd', [ &$template, true ] );
-				$hookContents = ob_get_contents();
-				ob_end_clean();
-				if ( !trim( $hookContents ) ) {
-					$hookContents = '';
-				}
-			}
-		}
-		// END hack
-
 		$labelId = Sanitizer::escapeId( "p-$name-label" );
 
 		if ( is_array( $content ) ) {
@@ -192,8 +173,6 @@ class TimelessTemplate extends BaseTemplate {
 					);
 				}
 			}
-			// Add in SkinTemplateToolboxEnd, if any
-			$contentText .= $hookContents;
 			$contentText .= Html::closeElement( 'ul' );
 		} else {
 			$contentText = $content;