Oilpan: Fix Heap::isConsistentForGC which only checks the heap for one attached thread at this poin…

Source/heap/Heap.cpp

Index: Source/heap/Heap.cpp
diff --git a/Source/heap/Heap.cpp b/Source/heap/Heap.cpp
index c7e1e047de31e7bb77ab5ada16964a2a31fe4e3e..88a6e8b80c33a29950e8fc8b1f2d68fcd3092d4e 100644
--- a/Source/heap/Heap.cpp
+++ b/Source/heap/Heap.cpp
@@ -1356,8 +1356,10 @@ bool Heap::isConsistentForGC()
 {
     ASSERT(ThreadState::isAnyThreadInGC());
     ThreadState::AttachedThreadStateSet& threads = ThreadState::attachedThreads();
-    for (ThreadState::AttachedThreadStateSet::iterator it = threads.begin(), end = threads.end(); it != end; ++it)
-        return (*it)->isConsistentForGC();
+    for (ThreadState::AttachedThreadStateSet::iterator it = threads.begin(), end = threads.end(); it != end; ++it) {
+        if (!(*it)->isConsistentForGC())
+            return false;
+    }
     return true;
 }