Fix SimpleKey equality with array argument

Prior to this commit, an array argument was not handled properly in
SimpleKey#equals and SimpleKey#hashCode. As a result, two method
invocations with the same array argument lead to two different keys
and therefore two different entries in the cache.

This commit uses deepEquals and deepHashCode to properly handle
methods that have arguments that are array types.

Issue: SPR-11505
Merge pull request #477 from candrews/patch-1

* patch-1:
  Fix SimpleKey equality with array argument