[mlir][tensor] Improve size inference in tiling tensor.pack ops.

[mlir][tensor] Improve size inference in tiling tensor.pack ops.

The sizes of input operands need being clampled only when there are
incomplete tiles, i.e., the padding value is set. The shape input slice
can be folded into constants when they are static shapes and tiling
sizes.

Reviewed By: chelini

Differential Revision: https://reviews.llvm.org/D144604