bsaes, in its current incarnation, hits various pathological behaviors
at different input sizes. Make it easy to experiment around them.
Bug: 256
Change-Id: Ib6c6ca7d06a570dbf7d4d2ea81c1db0d94d3d0c4
Reviewed-on: https://boringssl-review.googlesource.com/c/34876
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>