GitLab

* Added binary builtinMsgFunc forward() for heterograph

* Added backward for u_op_v

* Supports all binary builtin forward

* Supports binary message funcs with reduce func sum

* lint check

* removed import torch from unittest

* enabled GPU test

* lint check

* Fixed docstrings

* rename func get_hs_id

* edited comment
Co-authored-by: Israt Nisa <nisisrat@amazon.com>