Split up compiler.cpp (#15355)

Split up compiler.cpp (#15355)

Summary:
This separates the different parts of compiler.cpp to make their relationship more clear. In particular it adds:

* sugared_value.{h,cpp} - all the public SugaredValues that the compiler defines and a few that were inside compiler.cpp
* type_parser.{h, cpp} - Turns TreeRef's defining types into TypePtr
* schema_matching.{h, cpp} - infrastructure for matching arguments against overloaded schema and emitting builtin operators with a particular schema.
Retains:
* compiler.{h, cpp} - now responsible simply for the `defineMethodsInModule` infra structure.

Some utility functions like inlineCallTo have moved to ir.h.

Only thing that is not a move is some changes in module.h/cpp that remove multiple returns from `Method::emit_call_to`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/15355

Reviewed By: suo, wanchaol

Differential Revision: D13507524

Pulled By: zdevito

fbshipit-source-id: 69ec936a9ff1a383c12a883616346b219c72e393