In `WP_Term_Query`, accept a string value for `taxonomy`.

Props endocreative.
Props ocean90 for review.
Fixes #37545.
Built from https://develop.svn.wordpress.org/trunk@38181


git-svn-id: http://core.svn.wordpress.org/trunk@38122 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-term-query.php

@@ -219,7 +219,7 @@ class WP_Term_Query {
 			$query = $this->query_vars;
 		}
 
-		$taxonomies = isset( $query['taxonomy'] ) ? $query['taxonomy'] : null;
+		$taxonomies = isset( $query['taxonomy'] ) ? (array) $query['taxonomy'] : null;
 
 		/**
 		 * Filters the terms query default arguments.

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-alpha-38179';
+$wp_version = '4.7-alpha-38181';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.