Plugin Editor: Use `include_once` instead of `include` in `plugin_sandbox_scrape()` to fix unit tests broken with [41560].

See #39766.

Built from https://develop.svn.wordpress.org/trunk@41561


git-svn-id: http://core.svn.wordpress.org/trunk@41394 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/plugin.php

@@ -1909,7 +1909,7 @@ function plugin_sandbox_scrape( $plugin ) {
 	$old_wp_actions = $wp_actions;
 	array_map( 'remove_all_actions', array_keys( $tested_actions ) );
 
-	include( WP_PLUGIN_DIR . '/' . $plugin );
+	include_once( WP_PLUGIN_DIR . '/' . $plugin );
 
 	// Trigger key actions that are done on the plugin editor to cause the relevant plugin hooks to fire and potentially cause errors.
 	foreach ( $tested_actions as $action => $args ) {

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-alpha-41560';
+$wp_version = '4.9-alpha-41561';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.