Don't snap nonlinear TF parameters after regression

It's great to have "nice" values, and this actually moves error in both
directions (depending on the profile), but there's no principled reason
to be doing this.

Change-Id: I9952b13cb877df9fc020443cdd8512e641609356
Reviewed-on: https://skia-review.googlesource.com/117920
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
12 files changed