zephyr: Create a test runner for the samples
zephyr: Create a test runner for the samples

Enhance the test runner so that it can verify the output of the tests by
itself.  This needs the console to be logged to a file, but otherwise
works the same as the current test runner.

Also, the build results are placed in a log file, so that it is easier
to see what is happening.

Signed-off-by: David Brown <0af22db655f3ade5845314d695c1f4910314b0cb@linaro.org>

ATmobica/mcuboot,runtimeco/mcuboot,runtimeco/mcuboot,tamban01/mcuboot,utzig/mcuboot,ATmobica/mcuboot,ATmobica/mcuboot,utzig/mcuboot,tamban01/mcuboot,runtimeco/mcuboot,tamban01/mcuboot,runtimeco/mcuboot,utzig/mcuboot,runtimeco/mcuboot,utzig/mcuboot,utzig/mcuboot,tamban01/mcuboot,tamban01/mcuboot,ATmobica/mcuboot,ATmobica/mcuboot