Add a pool of small cat1 constants to the verifier.

This avoids creating constants in roughly half the cases seen in boot/core.
Also, strengthen the types on a few of the RegTypeCache routines, add some
documentation and move methods to the appropriate location and out of being
public when possible.

Change-Id: I384189d51d8f097bb7f744c0f6275dee4bb11302
4 files changed