Remove DEPRECATED_beginRecording().

Remove DEPRECATED_beginRecording().

This removes:
  1) ability to record old pictures with SkPictureRecorder;
  2) a couple tests specific to the old backend.

The functionality of DEPRECATED_beginRecording() now lives in
(private) SkPicture::Backport(), which is the only place we
need it now.

BUG=skia:
TBR=reed@google.com

Review URL: https://codereview.chromium.org/618303002