[Torch] Support Python list, more realistic recurrent networks (apach…

…e#5306)

* use funcs from prelude, pass around convert_map

* get relay input type from user ishape

* handle tuple unpack

* experimenting with static tensor array

* use prelude concat instead of cons + rev

* minor clean up

* fix layer norm conversion bug, unwrap tensor array

* add infer shape on tensor array

* pass around prelude for now

* compile worked but runtime error

* fix tensor array wrapping

* begin list dynamic test

* is_list_dynamic first version

* finish dynamic list test

* a few fix

* use shape_of function if Any is found

* improve size conversion

* working on adding free vars to loop block

* fixed inlined inner loop issue

* clean up free var handling

* add support for tensor array concat

* adding ta concat on last axis

* fix concat, but got runtime error

* disable concat on axis -1 for now

* add lstm tests

* revert unrelated change

* fix stacked bidir test

* minor fix to test

* relax tol a bit, revert dnnl change to avoid conflict

* simplify infer type, use input tensor shape rather than concat shape

* more shape fix