Add a virtual test suite for TargetedStyleRecalc.

BUG=335247
R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/148113009

git-svn-id: svn://svn.chromium.org/blink/trunk@166341 bbb929c8-8fbe-4397-9dbb-9b2b20218538