[parser] disallow language mode directive in body of function with non-simple parameters

test/mjsunit/strong/destructuring.js

Index: test/mjsunit/strong/destructuring.js
diff --git a/test/mjsunit/strong/destructuring.js b/test/mjsunit/strong/destructuring.js
index 67fe2ef4f163a699fecf24e1721c4ed5c8b3d691..3145dcfb4d9312235c63ed894eb5db618235f135 100644
--- a/test/mjsunit/strong/destructuring.js
+++ b/test/mjsunit/strong/destructuring.js
@@ -6,7 +6,10 @@
 // Flags: --harmony-arrow-functions --strong-mode --allow-natives-syntax
 
 (function() {
-  function f({ x = function() { return []; } }) { "use strong"; return x(); }
+  var f = (function() {
+    "use strong";
+    return function f({ x = function() { return []; } }) { return x(); };
+  })();
   var a = f({ x: undefined });
   assertTrue(%IsStrong(a));
 
@@ -19,7 +22,10 @@
   assertFalse(%IsStrong(a));
 
   function outerf() { return []; }
-  function f2({ x = outerf }) { "use strong"; return x(); }
+  var f2 = (function() {
+    "use strong";
+    return function f2({ x = outerf }) { return x(); };
+  })();
   a = f2({ x: undefined });
   assertFalse(%IsStrong(a));
 })();