update software DM/nanobench configs for color testing

- Rename 'srgbnl' to just 'srgb'.
- Add 'narrow' and 'enarrow' for testing a gamut narrower than sRGB.

Tested by running xfermodes2 in DM... all look different, what a mess.
I also ran a few nanobenches and they seemed somewhat sane.

Change-Id: Iacdc391dc0eef4153a76f5b4f78d72c57a4371ee
Reviewed-on: https://skia-review.googlesource.com/135871
Commit-Queue: Mike Klein <mtklein@chromium.org>
Auto-Submit: Mike Klein <mtklein@chromium.org>
Reviewed-by: Brian Osman <brianosman@google.com>
12 files changed