Backed out changeset 83f4f6f435cf (bug 734861) for mochitest-5 timeouts.
Bug 895340 - Fix error reporting of JS exceptions from C++ (r=bholley)
Bug 892225 - backout changeset b4426d926b31.
Backed out changeset f24d81b85929 (bug 895182) for Windows build failures on a CLOSED TREE
bug 896875 - [WebGL 2.0] WebGL2 unable to create context. r=bjacob
Bug 896842 - Implement mozilla::DoublesAreIdentical.  r=luke