* [Relay][VM]Compiling pattern matching

* Fix lint

* Remove debug code

* Move TreeNode definition

* merge ifi and selecti, todo: remove them

* fix lint

* remove ifi and selecti

* rename GetTagi to GetTag

* fix dltype

* fix more dltype

* Generalize If and select, and rename to Ifi and Selecti

* Fix lint

* Rename Ifi to If

* Change register default to match value

* Remove bad specialization for Move

* Stop use Select

* Remove Select

* TreeNode refactor

* Change entry_func name

* Remove Cmp due to rebase issue