test: Use plural name for repeated field

BUG=chromium:1063474
TEST=./generate.sh

Change-Id: Idfa53190d05903d91ccdb044f6b199d915822a7b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2128006
Tested-by: Prathmesh Prabhu <pprabhu@chromium.org>
Auto-Submit: Prathmesh Prabhu <pprabhu@chromium.org>
Reviewed-by: Alex Zamorzaev <zamorzaev@chromium.org>
Commit-Queue: Alex Zamorzaev <zamorzaev@chromium.org>
2 files changed