D3D11: unbreak instanced indirect multidraw with ushort indices The baseInstance parameter was not being passed in the unsigned short index case. Bug: angleproject:8216 Change-Id: If660c6d4125bfd2aff8f4fd3a9171194635d21c6 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4627281 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>