`get_the_category_by_ID()` should be taxonomy-agnostic.

Prior to 4.9, this function was accidentally taxonomy-agnostic in most cases.
The fix in [40979] caused a regression in this function. For backward
compatibility, we make it explicit that the query is by ID only.

Merges [42367] to the 4.9 branch.

See #42771.

Built from https://develop.svn.wordpress.org/branches/4.9@42371


git-svn-id: http://core.svn.wordpress.org/branches/4.9@42200 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/category-template.php

@@ -104,7 +104,7 @@ function get_the_category( $id = false ) {
  */
 function get_the_category_by_ID( $cat_ID ) {
 	$cat_ID = (int) $cat_ID;
-	$category = get_term( $cat_ID, 'category' );
+	$category = get_term( $cat_ID );
 
 	if ( is_wp_error( $category ) )
 		return $category;