More checking on sizes and dim order during tensor parsing (#1514)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/1514

Ensure that the `sizes` and `dim_order` fields of `Tensor` are present before using them.

Also check that `sizes` and `dim_order` have the same number of elements instead of just assuming that they're the same.

Reviewed By: larryliu0820

Differential Revision: D52451748

fbshipit-source-id: 0207cf8c1730209342bdecc0fc8c822e200b6619