Fix regression in get_tag_link() since 4.9.

See [42364] for description of the problem.

Because `get_category_link()` is now totally taxonomy-agnostic, `get_tag_link()`
can become a simple wrapper.

Props juiiee8487, markjaquith.
See #42771.
Built from https://develop.svn.wordpress.org/trunk@42366


git-svn-id: http://core.svn.wordpress.org/trunk@42195 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/category-template.php

@@ -1111,17 +1111,7 @@ function walk_category_dropdown_tree() {
  * @return string Link on success, empty string if tag does not exist.
  */
 function get_tag_link( $tag ) {
-	if ( ! is_object( $tag ) ) {
-		$tag = (int) $tag;
-	}
-
-	$tag = get_term_link( $tag, 'post_tag' );
-
-	if ( is_wp_error( $tag ) ) {
-		return '';
-	}
-
-	return $tag;
+	return get_category_link( $tag );
 }
 
 /**