Fix fuzzer-discovered undefined behavior with NaN.

The fuzzer passed in a point with a Y coordinate of NaN; this eventually
caused an integer overflow while attempting to calculate
`SK_MaxS32FitsInFloat << 2`. We now detect the NaN and return false.

Change-Id: I79e51190006bce5e2c42935e1075261a3e16aa6d
Bug: oss-fuzz:36198
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/429099
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
1 file changed