tc: revisit expect script for platform tests

In line with the changes done in TF-A to unify messages printed by the
different sets of platform tests, rework their expect script to:

 - "Expect" the new strings.

 - Return an exit code based on the outcome of the tests
   (0 for success, -1 for failure).

This last point makes the test configurations utilizing this expect
script more robust to tests failures. Where previously they would have
indefinitely waited for a "Passed nv_counter_test" string that would
never be seen, thus causing the CI job to time out, they will now
detect the test failure early and terminate the CI job.

Change-Id: I3f52a87711900cd3f3465c4dc84982176ef184cc
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
1 file changed