Build Tools: Improve `local-env` start behaviour under Docker Toolbox.

Docker Toolbox requires port forwarding to be configured, but generates error when trying to forward a port that's already been taken.

This change removes clashing port forwarding rules before adding our own.

See #47767.


Built from https://develop.svn.wordpress.org/trunk@45819


git-svn-id: http://core.svn.wordpress.org/trunk@45630 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-alpha-45818';
+$wp_version = '5.3-alpha-45819';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.