Set-theoretic types: inference of all language constructs

[josevalim]

Major milestones:

• [x] Tracking of variables
• [x] Type inference of patterns
• [ ] Type inference of guards
• [ ] Type inference for function application and function definition
• [x] Type inference of return types

This is a more granular break down of what needs to be done:

• [x] Map and struct updates
• [x] Checking of all inlined functions from Kernel
• [x] Checking of all inlined conversion functions
• [x] Checking of __STACKTRACE__ and raising functions
• [x] Support for local calls
• [x] Support for remote calls
• [x] Support for __info__, module_info, and behaviour_info
• [x] Typing of :erlang inlined functions
• [x] for comprehensions
  • [x] generators
  • [x] :into
  • [x] :reduce
• [ ] with comprehensions
• [x] Detect never matching clauses and patterns (cond, case, try)
• [ ] Track precision in case and inferred clauses to perform elimination
• [ ] Detect overlapping clauses (case, receive, try, reduce)
• [ ] Exhaustiveness checks (case, try, cond, reduce)
• [x] Unused clauses in private functions
• [x] Tracking of mismatches in equality operators
• [x] Tracking of structs in ordered comparison operators
• [x] Move compile.protocols to parallel compiler
• [x] Type checking of protocol dispatch
• [x] Type checking of impls
• [x] Storing of inferred types in .beam files
• [ ] Infer based on all loaded applications
• [ ] Infer all Elixir modules at once

This was extracted from #13227 and will be followed up by #13881.