fix indexing for GROUP BYs and WINDOWs in INSERT and REPLACE statements in TRIGGERS

[jycor]

Using aggregation and window functions inside a select statement inside an insert source inside a trigger was causing problems. For example, a trigger defined like so:

create trigger trig before insert on t1
for each row
begin
  insert into t2
  select 
     max(id),
     first_value(id) over (partition by id order by id),
     ...
  from
     t3;
end;

The issue involved the Projections over the Group Bys. The scope for the group bys already contained the trigger's columns and are indexed uniquely, so we shouldn't include the trigger/parent scope.

[fulghum]

LGTM!