Bootstrap: Revert [38399] as it's broken /build/ and subsequently core.svn.wordpress.org.

The generated classmaps reference `/src/` files and operates in the assumption that the base directory is one level above `wp-settings.php`, which it isn't after our build processes are run.

See #36335


git-svn-id: https://develop.svn.wordpress.org/trunk@38402 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-http.php

@@ -7,7 +7,7 @@
  * @since 2.7.0
  */
 
-if ( ! class_exists( 'Requests', false ) ) {
+if ( ! class_exists( 'Requests' ) ) {
 	require( ABSPATH . WPINC . '/class-requests.php' );
 
 	Requests::register_autoloader();