Fix matrix input attributes and formats. We can't assume we have a simple mapping between input attribs and shader attribs. The app specifies matrix input attribs as several vector inputs, while the shader uses a single matrix type. BUG=angle:576 Change-Id: I4e3cdde4a14a5f06b86052dfe0325113cbe8e599 Reviewed-on: https://chromium-review.googlesource.com/189193 Reviewed-by: Shannon Woods <shannonwoods@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>