General: Fix PHP 8.5 deprecation warning in unit test.

This removes a spurious `echo` from an output buffer callback.

Follow-up to [60936].

Props swissspidy, jorbin, westonruter.
See #43258.


git-svn-id: https://develop.svn.wordpress.org/trunk@60945 602fd350-edb4-49c9-b593-d223f7449a82

Author: westonruter

tests/phpunit/tests/template.php

@@ -577,7 +577,6 @@ static function ( string $buffer ) use ( &$filter_args ): string {
 
 				$p = WP_HTML_Processor::create_full_parser( $buffer );
 				while ( $p->next_tag() ) {
-					echo $p->get_tag() . PHP_EOL;
 					switch ( $p->get_tag() ) {
 						case 'HTML':
 							$p->set_attribute( 'lang', 'es' );