[svg] Remove primitive type wrappers

SkSVGPrimitiveTypeWrapper must have served some purpose in the past
(maybe? I have no memory of this place :P), but now it basically does
templated-nothing.

Well...

Change-Id: Id93487c345ea075d09b14024f4bcd2f987789518
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/282680
Reviewed-by: Tyler Denniston <tdenniston@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
11 files changed