* Run Debian package creation in a Docker container.
* Upload archives from Docker host (the container lacks credentials).
* Remove BUILDBOT_BUILDERNAME environment variables from test matrix:
They are overwritten in the recipe.
Change-Id: I90d7747e64231bdb745c85030a9cecf256adbaf0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/94542
Reviewed-by: William Hesse <whesse@google.com>
Alexander Thomas