[parser] use-strict directives in function body affect init block

test/mjsunit/strong/destructuring.js

+// Copyright 2015 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: --harmony-destructuring --harmony-computed-property-names
+// Flags: --harmony-arrow-functions --strong-mode --allow-natives-syntax
+
+(function() {
+  function f({ x = function() { return []; } }) { "use strong"; return x(); }
+  var a = f({ x: undefined });
+  assertTrue(%IsStrong(a));
+
+  // TODO(rossberg): Loading non-existent properties during destructuring should
+  // not throw in strong mode.
+  assertThrows(function() { f({}); }, TypeError);
+
+  function weakf({ x = function() { return []; } }) { return x(); }
+  a = weakf({});
+  assertFalse(%IsStrong(a));
+
+  function outerf() { return []; }
+  function f2({ x = outerf }) { "use strong"; return x(); }
+  a = f2({ x: undefined });
+  assertFalse(%IsStrong(a));
+})();