toolchain: pass additional_args in Bundle request

BundleToolchainRequest needs to pass any additional arguments that were
passed to PrepareForBuild.

BUG=chromium:1019868
TEST=generate

Change-Id: I3273a784d62aad11d7e9f0f1ce821a4bfc20dfad
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2056750
Reviewed-by: David Burger <dburger@chromium.org>
Commit-Queue: LaMont Jones <lamontjones@chromium.org>
Tested-by: LaMont Jones <lamontjones@chromium.org>
3 files changed