Stop turning off the overlap map with --enable-bleeding-edge-rendering-fast-paths

We are doing this because we do not intend to launch turning off the overlap map just yet. The primary reason is that at present, turning off the overlap map causes too much of an increase in rasterization cost on top pages.

BUG=351471

Review URL: https://codereview.chromium.org/196023004

git-svn-id: svn://svn.chromium.org/blink/trunk@169041 bbb929c8-8fbe-4397-9dbb-9b2b20218538