Remove the dependency of Zone on Isolate

src/compiler/ia32/instruction-selector-ia32.cc

Index: src/compiler/ia32/instruction-selector-ia32.cc
diff --git a/src/compiler/ia32/instruction-selector-ia32.cc b/src/compiler/ia32/instruction-selector-ia32.cc
index 7b6b721a376e5441ed704ecf9c9922324de9d328..7f82a5ce38447a515e15b0a897704fb504dc86b6 100644
--- a/src/compiler/ia32/instruction-selector-ia32.cc
+++ b/src/compiler/ia32/instruction-selector-ia32.cc
@@ -31,7 +31,8 @@ class IA32OperandGenerator FINAL : public OperandGenerator {
         // Constants in new space cannot be used as immediates in V8 because
         // the GC does not scan code objects when collecting the new generation.
         Unique<HeapObject> value = OpParameter<Unique<HeapObject> >(node);
-        return !isolate()->heap()->InNewSpace(*value.handle());
+        Isolate* isolate = value.handle()->GetIsolate();
+        return !isolate->heap()->InNewSpace(*value.handle());
       }
       default:
         return false;