Remove redundant SkDoubleIsNaN function

Skia already has SkIsNan in SkFloatingPoint.h

This was also causing a warning on some versions of GCC.

Change-Id: I1dc3ab8603141a647592dcd3524006242de94ccd
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/924398
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Kaylee Lubick <kjlubick@google.com>
Auto-Submit: Kaylee Lubick <kjlubick@google.com>
3 files changed