Revert "added sk_FragCoord support to skslc"

This reverts commit ce33f10677630e34187b661a02161378d8304d68.

Reason for revert: Breaking many gpu bots

Change-Id: I94c813ed6a9311458c872f74bb1b0792f46ff414
Reviewed-on: https://skia-review.googlesource.com/5737
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
33 files changed