scripts: twister: Add TestCase status printing

When at verbosity 1, we print out the status of TestInstances.
This makes it harder to notice changes at TestCase level,
which require perusing the logs.

This adds TestCase status and reason printing
if verbosity level is 2 or more.
Reason printing is suppressed if the reason is empty or None.

Signed-off-by: Lukasz Mrugala <lukaszx.mrugala@intel.com>