Revert "Add multitexture support to text and path shaders"

This reverts commit 7f754260f7fc2ae0326a072dd2f0429e584f8ca0.

Reason for revert: Bot failures.

Original change's description:
> Add multitexture support to text and path shaders
> 
> This does not add additional textures to the atlases, just adds the
> ability to access those textures in the shaders.
> 
> Bug: skia:3550
> Change-Id: I636b329a6f748b6753f5f92a70066fb412623df2
> Reviewed-on: https://skia-review.googlesource.com/43000
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Jim Van Verth <jvanverth@google.com>

TBR=jvanverth@google.com,bsalomon@google.com,robertphillips@google.com

Change-Id: I5c28ea48ed9bdde2cd936ef4f96fc720d5e4b4a5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:3550
Reviewed-on: https://skia-review.googlesource.com/44162
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
5 files changed