Ensure program state for multi-draw entry points If the currently bound program is being relinked, Context::prepareForDraw needs to wait until it's ready before syncing the backend state. Aligned all three no-op draw context helpers. Fixed: angleproject:406814763 Change-Id: I10eed90bb2fe853b558291fc8fe17d13652e0420 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6405536 Commit-Queue: Alexey Knyazev <lexa.knyazev@gmail.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>