add arguments with getopt to concurrent tester

- add ability to run for multiple iterations
- can also run non-threaded for comparison to threaded case

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>