dexanalyze: Improve field analysis.

Analyze also SGET/SPUT and better estimate the savings based
on given field index and in/out cutoff.

Experiments with core-oj indicate that the cutoffs 16/16 are
good for IGET/IPUT but SGET/SPUT would benefit more from
32/8 (assuming we want to use 8 bits together for the field
index and in/out).

Test: Manually run dexanalyze.
Change-Id: Id7cddaf20be4b345516777be6fbc599aed79ac5b
2 files changed