Remove the _ANGLE targets from the GN build. They are no longer needed by Chromium. BUG=522967 Change-Id: I187eed52378a58f3ea24c3e21082c6a93e56da7f Reviewed-on: https://chromium-review.googlesource.com/325330 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Corentin Wallez <cwallez@chromium.org>