As required by the GLES1 VertexPointerTest.

Bug: angleproject:5751
Change-Id: I889d136a2f76b0b9c256ffc9176c08a8c2b03a08
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2756534Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Cody Northrop <cnorthrop@google.com>
Commit-Queue: Lubosz Sarnecki <lubosz.sarnecki@collabora.com>