Bug 873142 - Do not shrink Arrays when tenuring; r=billm

The JITs assume that the capacity will not change between the initarray and the
actual initialization.

--HG--
extra : rebase_source : 53a3fe20f7fc687869ee303f58fbfa1bcf7324be
Bug 870496 - Purge moved objects in the NewObjectCache on minor GC; r=billm

--HG--
extra : rebase_source : 8d4b7df4cff1df4f1fc1de88e823a3e7541a55df
Bug 873136 - Only store the JSRuntime on the minor tracer once; r=billm

--HG--
extra : rebase_source : 76fc04c63d69041cd1133da2c7fa386d711ad0af