make float divide-by-zero fatal

Change-Id: I9ba1caa4862bdf9ffc9c0e637bd69cce91fd8468
Reviewed-on: https://skia-review.googlesource.com/c/168740
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
10 files changed