Backed out 6 changesets (bug 663778) for browser_dbg_listtabs-02.js leaks on a CLOSED TREE.

Backed out changeset cbd200206f9b (bug 663778)
Backed out changeset b0b74401e614 (bug 663778)
Backed out changeset df5255cffbfa (bug 663778)
Backed out changeset e6d0dd124356 (bug 663778)
Backed out changeset 134f77474941 (bug 663778)
Backed out changeset 456609873c5f (bug 663778)