we have some rules that change output's nullable in rewrite step. So we need a rule to adjust nullable at the end of rewrite step.
TODO
- remove the output slot map
- add nullable compare into slot reference
- use exprid to compare two slot if do not need to compare nullable
- merge all rules into one to adjust all type plans
1. generate lots of aggregate functions
2. support `group_concat(columns order by order_columns)` grammer
3. support and generate array aggregate/scalar functions, like `array_union`. we should support array grammar in the future, e.g. `select [1, 2, 3]`
4. add `checkLegalityBeforeTypeCoercion` and `checkLegalityAfterRewrite` function to check the legality of expression before type coercion and after rewrite, copy the semantic check of `FunctionCallExpr` to the checkLegality; remove the `ForbiddenMetricTypeArguments`; move the check of aes/sm4 crypto function from translator to checkLegalityBeforeTypeCoercion
5. refactor the `NullableAggregateFunction`: distinct is the first parameter, alwaysNullable is the second parameter; Fix some wrong initialize order: some function invoke super(distinct, alwaysNullable) but some function invoke super(alwaysNullable, distinct)
