Fix test pattern in zts-report.py

The pattern was not updated to match when the test output changed to
include a platform identifier for platform specific tests.

Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@ixsystems.com>
Closes #9750