Windows toolchain still needs relies on gyp.

R=sergiyb@chromium.org

Bug: v8:6105, chromium:826218
Change-Id: If7fba3cf986daa23a748681c3e6f1527af68b622
Reviewed-on: https://chromium-review.googlesource.com/980494Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52259}