Only support ES3 if texture swizzling is available On OSX 10.8 with an Intel HD 3000 we were wrongly exposing ES3 when texture swizzling was not available. BUG=angleproject:891 Change-Id: If71acdc1943ab2f013dc80cd28eab130c32fb201 Reviewed-on: https://chromium-review.googlesource.com/303392 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tryjob-Request: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Corentin Wallez <cwallez@chromium.org>