This serves as an example of table-driven benchmarks which are analoguous to the common pattern for table-driven tests.

Change-Id: I47f94c121a7117dd1e4ba03b3f2f8bcb5da38063
Reviewed-on: https://go-review.googlesource.com/23470
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>