Arrays containing Closure object(s) still attempted serialized with @backupStaticAttributes enabled

[Shne]

line 309 in PHPUnit/Util/GlobalState.php: if (!$value instanceof Closure) { checks whether the $value object is an instance of Closure and skips serialization of that object if that's the case, when the annotation @backupStaticAttributes is enabled.

However, it doesn't check whether it is an array and any of the contained objects are instances of Closure resulting in an Exception when that is the case.

[whatthejeff]

This is a duplicate of #451.