Revert "Revert "SkNx basically always is fast now.""

This reverts commit 8ba64d1996ba6c9ecfb12132cdab7d5d99af7456.

Reason for revert: does not appear to have been blocking the roll.

Original change's description:
> Revert "SkNx basically always is fast now."
> 
> This reverts commit 21f783829619186442041de6008f7f58f4f6250d.
> 
> Reason for revert: roll?
> 
> Original change's description:
> > SkNx basically always is fast now.
> > 
> > We had this SKNX_IS_FAST hanging around from before Chrome always built with NEON.
> > 
> > CQ_INCLUDE_TRYBOTS=skia.primary:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD
> > 
> > Change-Id: Ia5cc0323b3ef052192e2903f961aee11eb3f82d8
> > Reviewed-on: https://skia-review.googlesource.com/5946
> > Commit-Queue: Mike Klein <mtklein@chromium.org>
> > Reviewed-by: Mike Reed <reed@google.com>
> > Reviewed-by: Florin Malita <fmalita@chromium.org>
> > 
> 
> TBR=mtklein@chromium.org,fmalita@chromium.org,reed@google.com,reviews@skia.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> 
> Change-Id: I0e57285c68eae0a64213fe29ea4cca5519777954
> Reviewed-on: https://skia-review.googlesource.com/6040
> Commit-Queue: Mike Klein <mtklein@chromium.org>
> Reviewed-by: Mike Klein <mtklein@chromium.org>
> 

TBR=mtklein@chromium.org,reviews@skia.org,fmalita@chromium.org,reed@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: I230dd4c2abb2d14ffc302be5376b9eaacbbeafcc
Reviewed-on: https://skia-review.googlesource.com/6026
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
4 files changed