Add 1/16th pixel offset when drawing non-AA points/lines

This nudge ensures that pixel-aligned non-AA'd draws fill the desired
fragment.

Coupled with http://review.skia.org/665816, we're moving this logic from
Skia to Android so that the prerotation matrix can be properly accounted
for. Offseting only in Skia without accounting for prerotation  meant
the device-space Y offset could be applied in the wrong direction when
using Vulkan.

Equivalent change in T: Idfb5027fe3230f2c2b0cad224f2c7640e147ce4a

Bug: 254771190
Test: android.uirendering.cts.testclasses.ExactCanvasTests#testDrawLine
Change-Id: I975b62510a36312a395d1e254474bca726a9445d