[SVG] SVGAnimatedPointList migration to new SVG property impl.

This CL replaces SVGAnimatedPointList class with NewSVGProperty implementation, and moves matrixTransform out of platform/FloatRect to SVGPoint.

For details, see design doc: https://docs.google.com/document/d/1bg7CUyUszqdwmENY3JX6_PoQD6uHRCNcRPJMlC4qlkw/edit?usp=sharing

BUG=302829
BUG=308818
TBR=pdr@chromium.org

Review URL: https://codereview.chromium.org/132233016

git-svn-id: svn://svn.chromium.org/blink/trunk@165697 bbb929c8-8fbe-4397-9dbb-9b2b20218538