Backed out 6 changesets (bug 1386404) for XPCshell failures, at least on Linux. r=backout on a CLOSED TREE

Backed out changeset c80acdea24c1 (bug 1386404)
Backed out changeset 6224ffae752a (bug 1386404)
Backed out changeset 9eba087cf64a (bug 1386404)
Backed out changeset eac6eb517096 (bug 1386404)
Backed out changeset 802a00ea50e7 (bug 1386404)
Backed out changeset d7f697bac6ef (bug 1386404)