function PropTypeError(message) {
	  this.message = message;
	  this.stack = '';
	}
We use an Error-like object for backward compatibility as people may call
PropTypes directly and inspect their output. However we don't use real
Errors anymore. We don't inspect their stack anyway, and creating them
is prohibitively expensive if they are created too often, such as what
happens in oneOfType() for any type before the one that matched.