Propagate the concept of "packed opcode" values.

Dalvik now exposes a distinction between "packed" and regular opcode
values. The packed values are more densely defined in the range 0-0x1ff,
whereas the regular values are sparsely defined across the range 0-0xffff.

The only current use for packed values at this level is in opcode
usage reporting, but their use may expand over time.

Change-Id: Ie783b90cb2dcb9df8f3eb19a7c708a53906fdbe4