function toAccessorArray( arr ) {
	if ( arr && typeof arr === 'object' && isAccessorArray( arr ) ) {
		return arr;
	}
	return new AccessorArray( arr );
}
Converts an array-like object to a minimal array-like object supporting the accessor protocol.

## Notes

-   If a provided array-like object already supports the accessor protocol, the function returns the provided array-like object; otherwise, the function wraps the provided value in a object which uses accessors for getting and setting elements.

@param {Collection} arr - input array
@throws {TypeError} must provide an array-like object
@returns {(Collection|AccessorArray)} array-like object supporting the accessor protocol

@example
var o = toAccessorArray( [ 1, 2, 3 ] );
// returns <AccessorArray>

var v = o.get( 0 );
// returns 1