[Relay][RFC] Implement type checking for Any (#3221)

[Relay][RFC] Implement type checking for Any (#3221)

* Implement type checking for Any

Remove code generation related changes

Remove compile changes

Remove more

Remove unification hack

Add some code back that was needed, and clean up test

Refactor test cases

WIP

Implement TypeHint AST

Add test case which should fail

Remove unification changes, and fix bug with let rec

Restore unification for shapes

Improve error reporting while debugging

All examples type check

All examples type check

WIP

First version that works with hints, needs clean up

Remove dead code

Tweaks

Remove type hint

Remove unecessary type hint stuff

Remove more type hints

Clean up

Expose Any expression node

Address CR

Fix

Fix solver

Kill unecessary code

Fix

PyLint

Fix

Relocate loops

Fix license and test

Lint again

Lint again

Fix loops

Fix docstring

Fix template error

Fix compiler issue

Fix compile err

Remove more runtime changes

Restore buffer

Fix segfault

Fix

Fix arange

* Address feedback

* Fix typo

* Fix arange

* Fix op level3

* Fix issue with Python wrapper