The batching pass passes operands to the batched operation as a flat,
one-dimensional vector produced through a `tensor.collapse_shape`
operation collapsing all dimensions of the original tensor of
operands. Similarly, the shape of the result vector of the batched
operation is expanded to the original shape afterwards using a
`tensor.expand_shape` operation.
The pass emits the `tensor.collapse_shape` and `tensor.expand_shape`
operations unconditionally, even for tensors, which already have only
a single dimension. This causes the verifiers of these operations to
fail in some cases, aborting the entire compilation process.
This patch lets the batching pass emit `tensor.collapse_shape` and
`tensor.expand_shape` for batched operands and batched results only if
the rank of the corresponding tensors is greater than one.
