Bug 952295 - Fix an exact rooting hazard in CompileLazyFunction; r=sfink

--HG--
extra : rebase_source : 16f3adf53fafa2bc76ef4d8058923ee7818f303f
Bug 952285 - Clarify some code in TypeRepresentation for the hazard analysis; r=nmatsakis

--HG--
extra : rebase_source : dce9b8d79f645fd90e4049bf18e3056b25fd1740
Bug 951693 - Fix some newly-discovered rooting hazards in jsinfer.cpp; r=terrence