Backed out 3 changesets (bug 1076129, bug 1003448) for frequent xpcshell crashes on a CLOSED TREE.

Backed out changeset 3034162ee435 (bug 1003448)
Backed out changeset 086fe4b0ba14 (bug 1003448)
Backed out changeset 1babd65ebec7 (bug 1076129)