increase SkPoint3 normalize precision

using sqrtf() instead of sqrt() loses
too much precision.

Removed SK_CPU_FLUSH_TO_ZERO since
it was only used by the older code.

R=robertphillips@google.com

Bug: skia:
Change-Id: Ief2b969642e7dd423a2b07d2158f5e24eb487ca7
Reviewed-on: https://skia-review.googlesource.com/150380
Reviewed-by: Cary Clark <caryclark@skia.org>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Cary Clark <caryclark@skia.org>
Auto-Submit: Cary Clark <caryclark@skia.org>
3 files changed