Remove RenderFlowThread::initialLogicalWidth().

Re-implement updateLogicalWidth() in RenderMultiColumnFlowThread instead.

Review URL: https://codereview.chromium.org/266973005

git-svn-id: svn://svn.chromium.org/blink/trunk@173425 bbb929c8-8fbe-4397-9dbb-9b2b20218538