Fix for querying fields of different interface types

[flazoon]

Before this change, there was a single 'derivedTypes' param (needed by FRAGMENT_TYPE) passed to the query. This was causing issues with cases where the query was involving fields of different interface types.
e.g. the query below would not work properly

interface Int1{
   ...
}
interface Int2{
   ...
}
type Foo {
   field1: Int1
   field2: Int2
}
query {
   Foo {
      field1 {
         ...
      }
      field2 {
         ...
      }

   }
}

With this change there's one 'derivedTypes' per interface so fields of different interface types can be queried in the same query.

[johnymontana]

Thanks @flazoon!