Support TensorArray in BeamSearchDecoder state. (#13312)

* Support TensorArray in BeamSearchDecoder state.

* Use gather_nd for reordering and test more shapes.

* Add a flag to disable TensorArrays reordering.

* Add shape checks before reordering a TensorArray.

* Directly use float32 member of dtypes

* Directly access dimension value if defined

* Add more TensorArrays reordering constraints

* Do not unstack reordered TensorArrays

* Improve warning for ignored TensorArrays

* Consistent static and runtime dimensions check

* Use comparison operators

* Fix dynamic checks and add tests

* Make static checks error a warning

* Fix pylint errors