Bug 1035557 - Migrate crash checkpoints with the session so that we don't appear to crash during reset. r=ttaubert, a=lmandel

(grafted from a93ff5caef5fb5edfe476b4e984db3605d47e8b3)

--HG--
extra : source : 07e19701c947cc02fd4b7d76810f57bfeddcb162
extra : histedit_source : 563d45c1eef02fa3191befa554cf6c47e140a0ef