Fix failing test: $options will be ignored

Perhaps test should not look at this, given it's ignored by the class?

test/AbstractFactory/ReflectionBasedAbstractFactoryTest.php

@@ -174,7 +174,7 @@ public function testFactoryCanSupplyAMixOfParameterTypes()
         self::assertInstanceOf(TestAsset\ClassWithMixedConstructorParameters::class, $instance);
 
         self::assertEquals($config, $instance->config);
-        self::assertEquals([], $instance->options);
+        self::assertEquals(null, $instance->options);
         self::assertSame($sample, $instance->sample);
         self::assertSame($validators, $instance->validators);
     }