use precise is-normalized test in gm/p3.cpp

Change-Id: I894658882da92cb221be8355c8b1c7590c09895f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/303650
Commit-Queue: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed