1. fix function define of `Retention` inconsist, this function return tinyint on `FE` and return uint8 on `BE`
2. make assert_cast support cast to derived
3. change some static cast to assert cast
4. support sum(bool)/avg(bool)
Currently, there are some useless includes in the codebase. We can use a tool named include-what-you-use to optimize these includes. By using a strict include-what-you-use policy, we can get lots of benefits from it.
The column id check in VSlotRef::execute function before is too strict for fuzzy test to continuously produce random query. Temporarily loosen the check logic.
Moreover, there exists some careless call to VExpr::get_const_col, it might return a nullptr but not every function call checks if it's valid. It's an underlying problem.
