turn on more FP16 tests

A few upgrades to expect_close(),
and a few more places we need to use it.

I believe all that's left is to implement TFs.

Change-Id: I1a15f37b2a0d09cf61fdfbc77c48afcc617122a7
Reviewed-on: https://skia-review.googlesource.com/c/skcms/+/216374
Auto-Submit: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed