trusty:hwaes: enlarge the test buffers and correct enc/dec values

Use upto 16K of data in the test runs.  Also fix the test previously
encrypting and decrypting, or doing the same in the other way around so
that there is little difference in the measurements.

Bug: 329396218
Test: build.py --test com.android.trusty.hwaes.bench
Change-Id: I8002cd61b6f8b705276fa9e51f78ce1cc08764d2
2 files changed