move SFDot6 inverse table into SkAnalyticEdge

The 8K table in SkFDot6Constants.cpp is only used by SkAnalyticEdge and
its unit test, so to help LTO trim this when SkAnalyticEdge isn't used,
move it to SkAnalyticEdge.cpp and delete the unit test.  (I suspect the
table is never going to change.)

I've also moved setLine() out-of-line into SkAnalyticEdge.cpp to make
this work, and done a little bit of refactoring and renaming.

Change-Id: If1d234f387d100dd58d8860dccac000e5493a2c1
Reviewed-on: https://skia-review.googlesource.com/c/164182
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
8 files changed