move scalar functions out of SkVx.h

Now that we have skvx::map(), anyone can write this sort of
scalar-to-vector code.  There are no vector instructions for these, so
they'll never going to be particularly interesting for SkVx to provide.

We did work out _approximate_ versions of each of these for SkVM, and
that's what we use to evaluate these programs there.  So if this stuff
really matters we could port that logic back over to SkVx.h.

But in terms of pure refactoring, I think this is where we want to sit
until we decide to use those approximations.  I don't really want to
invest much time in the SkSLByteCode interpreter any more.

Change-Id: I4e595dee5fd9e608905305e46b2aebcab986c561
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/326277
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2 files changed