Revert of SkPDF: Add Sfntly to DEPS, gyp, SkUserConfig (patchset #7 id:570001 of...

Revert of SkPDF: Add Sfntly to DEPS, gyp, SkUserConfig (patchset #7 id:570001 of https://codereview.chromium.org/1134683006/)

Reason for revert:
break cros build

Original issue's description:
> SkPDF: Add Sfntly to DEPS, gyp
>
> Note: this can be disabled via:
>     GYP_DEFINES='skia_pdf_use_sfntly=0
>
> Warning: dm is 34% slower and uses 9% more memory.  This is
> okay.
>
> Motivation: We want to test this code path in DM, since it is
> always used by Chromium and Android.
>
> BUG=skia:3563
>
> Committed: https://skia.googlesource.com/skia/+/6a53b04e26749ea61f690ece408f2a1c0a5ad5bb

TBR=reed@google.com,mtklein@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:3563

Review URL: https://codereview.chromium.org/1128353004