Suppress error messages in ANGLE end2end tests on Nexus6P. GL errors are generated during initialization on this device. Suppress them until enough logging is in place to debug. BUG=998503 BUG=angleproject:3020 Change-Id: I74a51a661a930ea89b0234dcb3e6213288e75c86 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1774468 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Corentin Wallez <cwallez@chromium.org>