tools: tc-testing: Can pause just before post-suite

With option -P, the test script will pause just before
the post_suite functions are called.  This allows the tester to
inspect the system before it is torn down.

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