Bug 848199 - Rename the post barrier verifier nursery; r=billm

This allows us to use the post barrier verifier in parallel with generational
GC. It also makes the state tracking during verification much simpler.

js/src/jsweakmap.cpp

@@ -322,7 +322,7 @@ WeakMap_set_impl(JSContext *cx, CallArgs args)
         JS_ReportOutOfMemory(cx);
         return false;
     }
-    HashTableWriteBarrierPost(cx->runtime, map, key);
+    HashTableWriteBarrierPost(cx->runtime, map, key.get());
 
     args.rval().setUndefined();
     return true;