Disable paint invalidatin optimization about SVG transform change

The optimization prunes SVG subtree paint invalidation walking if
the container's transform changed. However, the transform changed
flag is only updated during layout causing:
- If multiple layouts before an invalidation, later layouts may
  clear the flag set by previous layout;
- For paint-only invalidation (after we use unified invalidation)
  the flag may remain uncleared if there is no layout causing
  incorrect pruning of tree walking.

SvgCubics doesn't show visible performance change with this patch.

BUG=394619

Review URL: https://codereview.chromium.org/412083003

git-svn-id: svn://svn.chromium.org/blink/trunk@179076 bbb929c8-8fbe-4397-9dbb-9b2b20218538