Mirror object for internal properties. Internal property reflects properties
not accessible from user code such as [[BoundThis]] in bound function.
Their names are merely symbolic.
@param {string} name The name of the property
@param {value} property value
@constructor
@extends Mirror
function InternalPropertyMirror(name, value) {
  %_Call(Mirror, this, MirrorType.INTERNAL_PROPERTY_TYPE);
  this.name_ = name;
  this.value_ = value;
}