[turbofan] escape analysis reducer no longer confused by TypeGuards it introduced itself

test/mjsunit/compiler/escape-analysis-12.js

Index: test/mjsunit/compiler/escape-analysis-12.js
diff --git a/test/mjsunit/compiler/escape-analysis-12.js b/test/mjsunit/compiler/escape-analysis-12.js
new file mode 100644
index 0000000000000000000000000000000000000000..20d5f2a1b0a4ba8731f068efeb0440c3a8a8c38a
--- /dev/null
+++ b/test/mjsunit/compiler/escape-analysis-12.js
@@ -0,0 +1,17 @@
+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --turbo --turbo-escape
+
+var x = {};
+x = {};
+function f() {
+  var y = {b: -1.5};
+  x.b = 1;
+  0 <= y.b;
+}
+f();
+f();
+% OptimizeFunctionOnNextCall(f);
+f();