Put an assertion in `test_nonexistent_array()` test.

The point of the test is to demonstrate that PHP doesn't throw a notice when
calling `unset()` on an undefined array key. To placate PHPUnit's useless test
detection, we add a redundant assertion.

Introduced in [25240].

See #36016.
Built from https://develop.svn.wordpress.org/trunk@36779


git-svn-id: http://core.svn.wordpress.org/trunk@36746 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.5-beta1-36778';
+$wp_version = '4.5-beta1-36779';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.