Revert of Refactoring of CPU NormalMap handling out into its own class (patchset...

Revert of Refactoring of CPU NormalMap handling out into its own class (patchset #13 id:240001 of https://codereview.chromium.org/2050773002/ )

Reason for revert:
GMs are crashing on Windows Test trybots

Original issue's description:
> SkLightingShader normal vector CPU computation refactor.
>
> The purpose of this change is to refactor the handling of normal maps out of SkLightingShader, laying the groundwork to eventually allow for multiple normal sources.
>
> This CL's base was the CL for GPU handling: https://codereview.chromium.org/2043393002/
>
> What this CL includes:
>
> - A refactor of the SkLightingShader context's code that deals with reading normals off of a normal map. This is now abstracted out into a NormalSource::Provider class that the context uses.
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2050773002
>
> Committed: https://skia.googlesource.com/skia/+/790a70118327a129cb6b48fabe80f4e184c1e67c

TBR=egdaniel@google.com,reed@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review-Url: https://codereview.chromium.org/2101653002