test: misc: add a test application for check_init_priorities

Add a test specifically for the check_init_priorities scripts.

The test creates a set of fake devices to exercise the three possible
conditions, run a build, run the check script and validate the script
output.

The check is meant to fail the build on error but that's bypassed in
this case as that would fail the twister run. That specific bit is
covered in unit tests anyway.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>
7 files changed