Reset the base level of textures before call glTexImage on Mac to prevent driver bugs that cause texture corruption. BUG=angleproject:3671 Change-Id: I90e94b8395a781a2142ef6be3af1d6117f084152 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1692975 Commit-Queue: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
