Global declarations created inside eval should not change configurability of existing properties

[bterlson]

Object.defineProperty(this, 'f', {
  enumerable: true,
  writable: true,
  configurable: false
});

print(JSON.stringify(Object.getOwnPropertyDescriptor(this, 'f')));
eval('function f() { return 2222; }');
print(JSON.stringify(Object.getOwnPropertyDescriptor(this, 'f')));

Expected: descriptor doesn't change
Actual: descriptor changes from configurable false to configurable true