Previously, when we vectorized scalars, we would not place them in the
constant buffer, so we could emit simple vectors like (0,0,0) or (1,1,1)
more than once. Now, we use `writeConstructorSplat` to vectorize, which
knows how to write constants.
Change-Id: Ic97c0ce5415fd46ff8c7fb7dac9205844633ef3a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/527921
Reviewed-by: Arman Uguray <armansito@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
b617bced6e