[turbofan] Test for FixedDoubleArray materialization.

R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2624113002
Cr-Commit-Position: refs/heads/master@{#42216}

test/mjsunit/compiler/escape-analysis-deopt-6.js

+// Copyright 2016 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-escape
+
+function f(x) {
+  var a = [0.1, 0.2, 0.3];
+  %_DeoptimizeNow();
+  return a.length;
+}
+
+assertEquals(3, f());
+assertEquals(3, f());
+%OptimizeFunctionOnNextCall(f);
+assertEquals(3, f());