port sample benchmarks from www.persistit.com

Several benchmarks have been developed to test persistit against other popular btrees, and need to be ported to run with our Akiban version. These benchmarks need to be integrated into the nightly runs and the performance framework so that regression can be detected.

Steps:
- Peter identify existing benchmark source code.
- Lu port benchmarks to new Akiban version of Persistit.
- Integrate benchmarks into nightly tests
- Integrate benchmarks into Performance framework