message: fixed error message for check and uncheck commands
diff: @@ -1148,7 +1148,7 @@ Selenium.prototype.getSpeed = function() {
  Selenium.prototype.findToggleButton = function(locator) {
  let element = this.browserbot.findElement(locator);
  if (element.checked == null) {
  - Assert.fail("Element " + locator + " is not a toggle-button."); // eslint-disable-line no-undef
  + throw new Error("Element " + locator + " is not a toggle-button."); // eslint-disable-line no-undef
  }
  return element;
  };
  