[mlir][tensor] Add e2e test for tensor.pack with dynamic tile sizes (#115698)
Adds an end-to-end test for `tensor.pack` with dynamic inner tile sizes.
While relatively simple (e.g., no vectorization), this example required
a few non-trivial fixes in handling `tensor.pack`:
* #114315, #114559, #113108.
The end goal for this test is to incrementally increase its complexity
and to work towards scalable tile sizes.