The _type_child_slots can be used to enable quick type checking optimization
by checking the whether the type index is within the bound.
This PR enables these static slots:
- Introduce a static assert to avoid the scenario when a developer forget to
_type_child_slots when the field is set for the type's parent.
- Revamp and assign static type index to common runtime objects
- Add a DumpTypeTable call to allow developer monitor the current situation
of type table and offers suggestions for the slots(ideally the slots equals
the number of children so there is no overflow.
Tianqi Chen
3cc4971990