General: Return early from `str_ends_with()` polyfill if both haystack and needle are empty.

Prior to PHP 7.0, `substr( '', -0, 0 )` returns `false` instead of an empty string, so the strict comparison further in the function did not work as expected.

This commit addresses a test failure on PHP < 7.0, making the function consistently return `true` if both haystack and needle are an empty string.

Follow-up to [52040], [56014], [56015].

See #58220.
Built from https://develop.svn.wordpress.org/trunk@56016


git-svn-id: http://core.svn.wordpress.org/trunk@55528 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/compat.php

@@ -482,8 +482,8 @@ if ( ! function_exists( 'str_ends_with' ) ) {
 	 * @return bool True if `$haystack` ends with `$needle`, otherwise false.
 	 */
 	function str_ends_with( $haystack, $needle ) {
-		if ( '' === $haystack && '' !== $needle ) {
-			return false;
+		if ( '' === $haystack ) {
+			return '' === $needle;
 		}
 
 		$len = strlen( $needle );

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.3-alpha-56015';
+$wp_version = '6.3-alpha-56016';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.