Bug 936911 - Export TabState.onSwapDocShells() in TabState.jsm r=billm

From adcf642ed40bccc0b6fed3232bcc733228d7b7da Mon Sep 17 00:00:00 2001
Bug 934206 - Disable browser_248970_b_perwindowpb.js for leaking r=ehsan

From 77547f79a335d3e84c717ea8757f59f06007900b Mon Sep 17 00:00:00 2001