Bound functions should also have configurable length

test/mjsunit/regress/regress-1419.js

Index: test/mjsunit/regress/regress-1419.js
diff --git a/test/mjsunit/regress/regress-1419.js b/test/mjsunit/regress/regress-1419.js
index 98a8b76b57939d96feae52e69656c0bf4a992f0e..55bcd7ccaa0eb88248013819c2df81d04146bffe 100644
--- a/test/mjsunit/regress/regress-1419.js
+++ b/test/mjsunit/regress/regress-1419.js
@@ -44,4 +44,12 @@ assertEquals(1, f1.length);
 var desc = Object.getOwnPropertyDescriptor(f1, 'length');
 assertEquals(false, desc.writable);
 assertEquals(false, desc.enumerable);
-assertEquals(false, desc.configurable);
+assertEquals(true, desc.configurable);
+
+Object.defineProperty(f1, 'length', {
+  value: 'abc',
+  writable: true
+});
+assertEquals('abc', f1.length);
+f1.length = 42;
+assertEquals(42, f1.length);