use print_shortest_float() for matrix values

Change-Id: I734400314e9d3b95b7ca342930d44ffeafc67d3b
Reviewed-on: https://skia-review.googlesource.com/c/skcms/+/399159
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
10 files changed