merge-into-chromeos: Automatically set CQ+1
merge-into-chromeos: Automatically set CQ+1

Since we have a chain of commits, we need to set all of
them to CQ+1 for the dry run to happen.
Unfortunately, the CQ will only ever run a single build
for a chain of commits. So the dry run will only happen
when all builds have finished.

BUG=b:213932296
TEST=./ci/kokoro/simulate build-merge-into-chromeos.sh

Change-Id: I1883b22ab97da604a4188528ccfb3231a23cb7f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3384220
Reviewed-by: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>
Tested-by: Dennis Kempin <cd09796fb571bec2782819dbfd33307f65b1c778@google.com>

google/crosvm,google/crosvm,google/crosvm,google/crosvm