Different call depth used in class hash comparison in gather class hashes

[marcuspang]

          Can you explain the reasoning behind merging like this? Why do we only count the call if it exists in both lists?

Also, what will this do if we have a calls on different layers. For example:
base_call -> call_1 -> call_2 -> call_3
native_call -> call_1 -> call_3
call_3 exists in both base and native, but it exists in base only because of call_2, which was not in native.

Originally posted by @PearsonWhite in #88 (comment)