Revert of - Add astcbitmap to gm slides (https://codereview.chromium.org/444093002/)

Reason for revert:
Breaking DM

Original issue's description:
> - Add astcbitmap to gm slides
> - Add additional ASTC formats
> - Add astc image decoder files
>
> Committed: https://skia.googlesource.com/skia/+/2fc05823fed4b9649338f3029cd1ba05ef49a02f

R=reed@google.com, robertphillips@google.com, halcanary@google.com
TBR=halcanary@google.com, reed@google.com, robertphillips@google.com
NOTREECHECKS=true
NOTRY=true

Author: krajcevski@google.com

Review URL: https://codereview.chromium.org/447343002
14 files changed