Testsuite: add option to insert delays, for very slow test platforms

Testsuite: add option to insert delays, for very slow test platforms

An emulated PPC, running as a VM on x86_64, was seeing testcase fails where
the trailing few log line were missing in munged output, despite on inspection
being present in the spool.  Adding a delay before the munge-and-compare
made the issue go away.