Fix TSAN issue wrt assertions in the optimizing compiler thread.

src/hydrogen-environment-liveness.cc

Index: src/hydrogen-environment-liveness.cc
diff --git a/src/hydrogen-environment-liveness.cc b/src/hydrogen-environment-liveness.cc
index d7501ac49e6fd2b519a1471a1f6d88543410d16d..726198d98b5359cfd26c66cbb89ecf5d03c1497a 100644
--- a/src/hydrogen-environment-liveness.cc
+++ b/src/hydrogen-environment-liveness.cc
@@ -84,8 +84,8 @@ void HEnvironmentLivenessAnalysisPhase::ZapEnvironmentSlotsInSuccessors(
       }
       HSimulate* simulate = first_simulate_.at(successor_id);
       if (simulate == NULL) continue;
-      ASSERT(simulate->closure().is_identical_to(
-                 block->last_environment()->closure()));
+      ASSERT(VerifyClosures(simulate->closure(),
+          block->last_environment()->closure()));
       ZapEnvironmentSlot(i, simulate);
     }
   }
@@ -97,7 +97,7 @@ void HEnvironmentLivenessAnalysisPhase::ZapEnvironmentSlotsForInstruction(
   if (!marker->CheckFlag(HValue::kEndsLiveRange)) return;
   HSimulate* simulate = marker->next_simulate();
   if (simulate != NULL) {
-    ASSERT(simulate->closure().is_identical_to(marker->closure()));
+    ASSERT(VerifyClosures(simulate->closure(), marker->closure()));
     ZapEnvironmentSlot(marker->index(), simulate);
   }
 }
@@ -241,4 +241,14 @@ void HEnvironmentLivenessAnalysisPhase::Run() {
   }
 }
 
+
+#ifdef DEBUG
+bool HEnvironmentLivenessAnalysisPhase::VerifyClosures(
+    Handle<JSFunction> a, Handle<JSFunction> b) {
+  Heap::RelocationLock for_heap_access(isolate()->heap());
+  AllowHandleDereference for_verification;
+  return a.is_identical_to(b);
+}
+#endif
+
 } }  // namespace v8::internal