Remove excess gl:: prefixing in validationES.cpp. Refactor only. Bug: angleproject:2747 Change-Id: I0ef7186daec54cd867ec2816f86f7205d836fd91 Reviewed-on: https://chromium-review.googlesource.com/1158609 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>