$getProperty method
Get a property by identifier on this instance
Implementation
@override
$Value? $getProperty(Runtime runtime, String identifier) {
  switch (identifier) {
    case 'toRadixString':
      return __toRadixString;
    case '|':
      return __bitwiseOr;
    case '&':
      return __bitwiseAnd;
    case '<<':
      return __shiftLeft;
    case '>>':
      return __shiftRight;
    case '^':
      return __bitwiseXor;
    case '~/':
      return __truncatediv;
  }
  return super.$getProperty(runtime, identifier);
}