@Override
    public Object create(Token payload) {
      return new ASTNode(payload);
    }
Creates an ASTNode for the given token. The ASTNode is a wrapper around
antlr's CommonTree class that implements the Node interface.

@param payload The token.
@return Object (which is actually an ASTNode) for the token.
parser/src/test/org/apache/hadoop/hive/ql/parse/HqlParser.java