new_variant: add end-to-end test

Add an end-to-end test for new_variant.py to verify that creating
firmware for a new variant still works.

BUG=b:167305316
TEST=See testdata/README.md for full details. Short version:
`cd testdata` then pick a reference board to test:
`./new_variant_fulltest.sh hatch`
`./new_variant_fulltest.sh puff`
`./new_variant_fulltest.sh volteer`
`./new_variant_fulltest.sh trembyle`
`./new_variant_fulltest.sh dalboz`
`./new_variant_fulltest.sh waddledee`
`./new_variant_fulltest.sh waddledoo`
Watch the output to see the build succeed and then clean up all of
the generated CLs. Run `repo status` to see that there aren't any
modified files hanging around.

Change-Id: I33157f41f398c0dc60a453584de71b538dd9d37c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/2393470
Tested-by: Paul Fagerburg <pfagerburg@chromium.org>
Reviewed-by: Rob Barnes <robbarnes@google.com>
Reviewed-by: Greg Edelston <gredelston@google.com>
Commit-Queue: Paul Fagerburg <pfagerburg@chromium.org>
3 files changed