Make assert less sensitive to rounding errors

Change-Id: I64b28e0cdcb7f44c1ded9c8d23f3b9c9add09861
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/268837
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Julia Lavrova <jlavrova@google.com>
2 files changed