Improve ValidateSuperClassDescriptors performance.

ValidateSuperClassDescriptors uses FindClass with the 2 class loaders that are
being used in validating method parameter types. The use of 2 class loaders
ensures at least one miss with LookupClass and thereby a call to
ClassLoader.loadClass which will then defer to the parent class loader eating
time. This change modifies the behavior to instead lookup types with a dex
cache, so that resolution and load class are only performed once per type.

Bug: 12804658
Change-Id: Ia7be1f7bab8175a6934fd59fc54e0829beed0198