3G: Begin migrating cellular autotests to use dependencies.

Instead of specifying different pools in suite_scheduler.ini, migrate
the cellular autotests to use DEPENDENCIES to specify the desired DUTs.
network_3GSmokeTest is the first test to migrate.  New control files
are added to specify the dependencies.  The main control file is
removed from the network3g suite in favor of the new control files.

BUG=chromium-os:35382
TEST=None

Change-Id: I0971080eeb52949abef1950686a92882278f93cd
Reviewed-on: https://gerrit.chromium.org/gerrit/36470
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Commit-Ready: Thieu Le <thieule@chromium.org>
Tested-by: Thieu Le <thieule@chromium.org>
8 files changed