Class's __proto__ should not be writable

[Ryosuke Niwa]

Fix the FIXME in ClassExprNode::emitBytecode:
// FIXME: Make the prototype non-configurable & non-writable.

[Ryosuke Niwa]

class A {}
class B extends A {
    constructor() {
        super();
    }
}
new B;
class C {
    constructor() {
        alert('FAIL')
    }
}
B.__proto__ = C;
new B;

should never alert FAIL.

[Keith Miller]

This is not valid anymore in the spec so... closing

[Keith Miller]

err... valid => true