Revert "Adds a GrGLPathRendering class that wraps the NV_path_rendering"

This reverts commit 5672da0fa54f31c9727568e9dd5fe82c6e1585bc.

This appears to be blocking the Skia roll by causing failures in the blink layout tests on the canvas-lost-gpu-context.html test.

The bisect for this can be seen at:

https://codereview.chromium.org/449473002/

Original issue's description:
> Adds a GrGLPathRendering class that wraps the NV_path_rendering
> extension and manages its various API versions. It also provides
> backup implementations when certain NVpr methods from later API
> versions are not present on the current system.
>
> Committed: https://skia.googlesource.com/skia/+/5672da0fa54f31c9727568e9dd5fe82c6e1585bc
14 files changed