tools: tc-testing: Command line parms

Separate the functionality of the command line parameters into "selection"
parameters, "action" parameters and other parameters.

"Selection" parameters are for choosing which tests on which to act.
"Action" parameters are for choosing what to do with the selected tests.
"Other" parameters are for global effect (like "help" or "verbose").

With this commit, we add the ability to name a directory as another
selection mechanism.  We can accumulate a number of tests by directory,
file, category, or even by test id, instead of being constrained to
run all tests in one collection or just one test.

Signed-off-by: Brenda J. Butler <bjb@mojatatu.com>
Acked-by: Lucas Bates <lucasb@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>