Fix extension check for xfb mode validation With geometry and tessellation shaders, it's possible to use different primitive modes between transform feedback and draw, as long as they are from the same class. The code accidentally allowed this only if both extensions are supported, but it should be allowed if either is. Bug: angleproject:428561247 Change-Id: Ia18d4ac15a3d0739ce18dc0e1f3d3f0b1aea621c Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6780744 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>