SVG: dedupe adjustFromToListValues

SVG{Length,Point,Number} have very similar implementations of adjustFromToListValues.
This CL dedupes it by moving it to SVGListPropertyHelper.

BUG=378670

Review URL: https://codereview.chromium.org/358083002

git-svn-id: svn://svn.chromium.org/blink/trunk@177074 bbb929c8-8fbe-4397-9dbb-9b2b20218538