The test was initializing an extra element at the end of a vertex buffer and never initializing it. I fixed this for one test but the bug was actually replicated into several. This fixes the bug by inializing the last vertex to the zero vertex value. Bug: angleproject:3951 Bug: angleproject:4163 Bug: angleproject:4258 Bug: angleproject:4269 Bug: angleproject:5258 Change-Id: I226406475340d756bfb7624d163abeca7b807f20 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2505551Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>