Bug 1196027 - check the actual current marking mode instead of the permanent intention, r=terrence

--HG--
extra : rebase_source : 1a2da1602094596a9b3f6f16c3eb6f511cff29b7
extra : amend_source : c130055fc3110874fef7661019d751a1448cbde3
extra : source : 9ca39133a30af07bb6b27d5742b2c5865caa3b31

js/src/jsgc.cpp

@@ -4034,7 +4034,7 @@ GCRuntime::markWeakReferences(gcstats::Phase phase)
         for (CompartmentIterT c(rt); !c.done(); c.next()) {
             if (c->watchpointMap)
                 markedAny |= c->watchpointMap->markIteratively(&marker);
-            if (marker.weakMapAction() != ExpandWeakMaps)
+            if (!marker.isWeakMarkingTracer())
                 markedAny |= WeakMapBase::markCompartmentIteratively(c, &marker);
         }
         markedAny |= Debugger::markAllIteratively(&marker);