Fix many bugs in brancher service

[rvantonder]

Bugs:

• Succs is a function not a class 😱. Always returns None causing succs.jmps to fail hard.
• Use of undefined variable self.succs 😱 😱
• Can't index into sets 😱
• dumps is never actually called 😱

Functionality: pretty sure it is dests - jmps to get falls, as in the code before this was refactored--also looks "right" when I compare actual IDA output.

[ivg]

Yeah, when I was refactoring it, I wasn't actually understanding what this code is doing and didn't have any tests to verify that my changes are correct. So I just made some initial approximation, though the sub vs class is really funny)) Thanks