getPropertyName_(nameTree) {
    let token = nameTree.literalToken;
    switch (token.type) {
      case IDENTIFIER:
        return createStringLiteral(token.value);
      default:
        if (token.isKeyword())
          return createStringLiteral(token.type);
        return new LiteralExpression(token.location, token);
    }
  }
Creates the expression to use as the name for:

  Object.defineProperty(object, name, descr)

@private
@param {Token} token
@return {ParseTree}