[mlir][sparse] avoid unnecessary tmp COO buffer and convert when lowering ConcatentateOp.

[mlir][sparse] avoid unnecessary tmp COO buffer and convert when lowering ConcatentateOp.

When concat along dim 0, and all inputs/outputs are ordered with identity dimension ordering,
the concatenated coordinates will be yield in lexOrder, thus no need to sort.

Reviewed By: aartbik

Differential Revision: https://reviews.llvm.org/D140228