[RAL] Reduce SVG tree walks

This is based on an earlier patch from <fs@opera.com>.

The performance regression mostly came from excessive tree walks
on SVG_SvgCubics (with only a tiny part of it came also from
extra invalidations).

This change re-introduces what
SVGRenderSupport::checkForSVGRepaintingDuringLayout was doing to
prevent invalidation by checking if your parent had a transform
change, except that we use it to avoid entire subtree walks.

On my Z620, this changes the results of SVG_SvgCubics as follows:
- RAL without patch: 16 ms (std: 0.5)
- RAL with patch: 8.8 ms (std: 0.4)
- Pre-RAL: 9.2 ms (std: 0.3)

BUG=381138

Review URL: https://codereview.chromium.org/327093003

git-svn-id: svn://svn.chromium.org/blink/trunk@175983 bbb929c8-8fbe-4397-9dbb-9b2b20218538