Optimize FloatIntervalSearchAdapter::collectIfNeeded by reducing calls to logical(Left/Right/Bottom)ForFloat.

Brings average page load time of bookish.com (from tough_layout_cases) from ~4100 ms to ~2800ms on my z620.

BUG=260903
R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/22463002

git-svn-id: svn://svn.chromium.org/blink/trunk@155958 bbb929c8-8fbe-4397-9dbb-9b2b20218538