print matrices as %.9g

The various printf() we use don't agree in rounding.
It's easy to get Emscripten or MSVC to disagree with
the rest.

I have tried:
  - %a
  - %g
  - %g forced to round up
  - %.8f
  - %.10f
  - %.11f

Change-Id: I6cdfd2bfc588f0e174f230bf2c282de11cb1414b
Reviewed-on: https://skia-review.googlesource.com/c/skcms/+/199327
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
48 files changed