Fix CacheManagerSuite to use Array

In addition, avoid using EasyMock for one of our tests, which expects
BlockManager#put to be called with an Array[Any] parameter. Even with
all the EasyMock matchers, it is impossible to match an Array[Any]
because of a combination of the following: (1) the fact that Arrays
are not covariant, (2) EasyMock provides `aryEq` matchers for all the
Java primitive types, which conflict with Any, and (3) EasyMock's super
general matchers like `anyObject` or `isA` also do not match for some
reason.