Ignores test for PHP 7.2+

The offending test breaks due to a representation change in the
deserialized (incomplete) object and can safely be ignored.

tests/UnserializeTest.php

@@ -232,6 +232,26 @@ public function test_double_unserialize_double_serialized()
         $this->assertInstanceOf('__PHP_Incomplete_Class', $unserialized);
     }
 
+    /**
+     * @requires PHP < 7.2
+     *
+     * In PHP 7.2+ the unserialized, incomplete object is not a stdClass object.
+     *
+     * That means instead of:
+     *
+     * stdClass Object &000000007bdb046700000000047a45c3 (
+     *     'value' => 'a:2:{i:0;s:4:"item";i:1;O:8:"stdClass":1:{s:5:"value";s:12:"s:5:"inner";";}}'
+     * )
+     *
+     * We get:
+     *
+     * __PHP_Incomplete_Class Object &000000007bdb047d00000000047a45c3 (
+     *     '__PHP_Incomplete_Class_Name' => 'stdClass'
+     *     'value' => 'a:2:{i:0;s:4:"item";i:1;O:8:"stdClass":1:{s:5:"value";s:12:"s:5:"inner";";}}'
+     * )
+     *
+     * We do not care about this changed representation and ignore this test instead for these versions.
+     */
     public function test_nested_serialized_object_in_serialized_object_can_be_deserialized()
     {
         $inner = new \stdClass();
@@ -243,7 +263,7 @@ public function test_nested_serialized_object_in_serialized_object_can_be_deseri
 
         $unserialized = Unserialize::unserialize($serialized, $options);
 
-        $this->assertEquals($outer,$unserialized);
+        $this->assertEquals($outer, $unserialized);
     }
 
     public function test_string_containing_serialized_literals_can_be_deserialized()