pp_test: Add level 3 regression test

The level 3 supported in the TF-M v1.2.0 release, it has been verifed in
the nightly job. Add the level 3 test in the per-patch test as it is an
important feature.

Signed-off-by: Karl Zhang <karl.zhang@arm.com>
Change-Id: Iac3db4b57d450059d39d90a78b16fc1fb1f56eab
1 file changed