ArrayCache instead of ApcCache in ChainTest

* Because there is no APC requirement int composer, this test cannot use
the ApcCache without checking the extension
* Intead of this one, let's use another ArrayCache to make tests pass
* Travis tests are not passing, with this change should pass
Merge pull request #54 from mmoreram/hotfix/test-array-instead-apc

ArrayCache instead of ApcCache in ChainTest