remove clipstack from lua -- deprecated

BUG=skia:

Change-Id: I7974b5921aeeabc9c58fdf76731d80b8f0702a70
Reviewed-on: https://skia-review.googlesource.com/7309
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
5 files changed