Fixed sampling non-SkSL FPs with coordinates

This fixes an issue where fragment processors which were not written
in pure SkSL did not interact properly with coordinate overrides.

Change-Id: I960173986fd8d6be7322f55ab0d81a533b6b89e5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/252916
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
10 files changed