[mlir] Fix TileUsingForOp attr-dict printing/parsing (#73261)

`TileUsingForOp` has an optional Attribute `interchange` which was given
in curly braces like this: `{interchange = [...]}`. The way this was
parsed meant that no `attr-dict` could be attached to the Op.
This patch adds printing / parsing of an `attr-dict` to the Op and
prints/parses the `interchange` Attribute separate from the
discardable Attributes.