In `wp_sanitize_redirect()`, don't eat `@` characters. According to RFC 3986, "@" is a perfectly valid character in a URL path or query string.

Adds unit test.

Props markjaquith.
Fixes #18818.

Built from https://develop.svn.wordpress.org/trunk@33707


git-svn-id: http://core.svn.wordpress.org/trunk@33674 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/pluggable.php

@@ -1232,7 +1232,7 @@ function wp_sanitize_redirect($location) {
 		){1,40}                              # ...one or more times
 		)/x';
 	$location = preg_replace_callback( $regex, '_wp_sanitize_utf8_in_redirect', $location );
-	$location = preg_replace('|[^a-z0-9-~+_.?#=&;,/:%!*\[\]()]|i', '', $location);
+	$location = preg_replace('|[^a-z0-9-~+_.?#=&;,/:%!*\[\]()@]|i', '', $location);
 	$location = wp_kses_no_null($location);
 
 	// remove %0d and %0a from location

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.4-alpha-33706';
+$wp_version = '4.4-alpha-33707';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.