function isReadOnly( arr ) {
	return ( flag( arr, 'READONLY' ) === true );
}
Tests whether an ndarray is read-only.

@param {ndarray} arr - input ndarray
@returns {boolean} boolean indicating whether an ndarray is read-only

@example
var array = require( '@stdlib/ndarray/array' );

var x = array( [ 1, 2, 3, 4 ], {
    'readonly': true
});
var bool = isReadOnly( x );
// returns true

x = array( [ 1, 2, 3, 4 ] );
bool = isReadOnly( x );
// returns false