Make assertion scopes thread safe.

src/ia32/macro-assembler-ia32.h

Index: src/ia32/macro-assembler-ia32.h
diff --git a/src/ia32/macro-assembler-ia32.h b/src/ia32/macro-assembler-ia32.h
index 340055ad86055e25045532a4320b7f69cb89d36b..1c2622ef5e0d79bf65c29c0489faaa6a19c4c107 100644
--- a/src/ia32/macro-assembler-ia32.h
+++ b/src/ia32/macro-assembler-ia32.h
@@ -276,7 +276,7 @@ class MacroAssembler: public Assembler {
   void PushHeapObject(Handle<HeapObject> object);
 
   void LoadObject(Register result, Handle<Object> object) {
-    ALLOW_HANDLE_DEREF(isolate(), "heap object check");
+    ALLOW_DEFERRED_HANDLE_DEREF(isolate(), "heap object check");
     if (object->IsHeapObject()) {
       LoadHeapObject(result, Handle<HeapObject>::cast(object));
     } else {
@@ -285,7 +285,7 @@ class MacroAssembler: public Assembler {
   }
 
   void CmpObject(Register reg, Handle<Object> object) {
-    ALLOW_HANDLE_DEREF(isolate(), "heap object check");
+    ALLOW_DEFERRED_HANDLE_DEREF(isolate(), "heap object check");
     if (object->IsHeapObject()) {
       CmpHeapObject(reg, Handle<HeapObject>::cast(object));
     } else {