Fix inversion logic when d of src or inv > 1

Bug: oss-fuzz:16584
Change-Id: Idc6d1b70104f1efcbfb849e68e8c91383018483e
Reviewed-on: https://skia-review.googlesource.com/c/skcms/+/235462
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
4 files changed