Test SAC experiments for performance.

[matthewhammer]

• Collect and report performance numbers for _sac versions, as we have already done for _arggen and _name
• I don't know what to expect for their performance, but I'd be surprised if they are ever much slower than _arggen. Typically, they should be faster than _arggen. I don't know how they will compare against _name. This comparison is the central question for these experiments.
• For a complete list of benchmarks to test, and for a handy want to test them for correctness (regression tests) see this file:
  https://github.com/plum-umd/adapton.ocaml/blob/master/script/test-correctness.sh