Make Function.length and Function.name configurable properties.

test/mjsunit/regress/regress-function-length-strict.js

Index: test/mjsunit/regress/regress-function-length-strict.js
diff --git a/test/mjsunit/regress/regress-function-length-strict.js b/test/mjsunit/regress/regress-function-length-strict.js
index 700f34a67ad301e80878fbe7f27fcd5b68794655..6f23df7964971249e3be90fcabfa514513b76540 100644
--- a/test/mjsunit/regress/regress-function-length-strict.js
+++ b/test/mjsunit/regress/regress-function-length-strict.js
@@ -37,5 +37,8 @@ var desc = Object.getOwnPropertyDescriptor(foo, 'length');
 assertEquals(3, desc.value);
 assertFalse(desc.writable);
 assertFalse(desc.enumerable);
-assertFalse(desc.configurable);
+assertTrue(desc.configurable);
 assertThrows(function() { foo.length = 2; }, TypeError);
+
+assertDoesNotThrow(function () { Object.defineProperty(foo, 'length', {value: 4}); });
+assertEquals(4, foo.length);