Alignment fix for IOSurface A wrong alignment was causing an issue in some tests. This CL doesn't fix any single WebGL conformance test entirely, but it fixes 564 of the 1292 failing sub-cases within the conformance/textures/webgl_canvas/* category. Bug: chromium:1099979 Change-Id: Id6051b24cb3c335d2f97f2c38c8de1dc7afde52f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3203790 Reviewed-by: Jonah Ryan-Davis <jonahr@google.com> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Alexis Hétu <sugoi@chromium.org>