public ArrayList<RexCall> getValidJdbcNode() {
      return validJdbcNode;
    }
FilterSupportedFunctionsVisitor traverse all of the Rex call and splits them into
two lists, one with supported jdbc calls, and one with not supported jdbc calls.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/jdbc/JDBCAbstractSplitFilterRule.java