[Stream] Handle tied operand result encodings in UnifyEncodingForGlobals 3/n (#22891)

When a dispatch has a tied operand whose encoding is being unified, the
result encoding must also be updated to match (verifier requirement).
Additionally, insert a re-encode op after the dispatch to convert the
result back to the original encoding for downstream users.

This is a rare case that exists primarily for correctness as a safe
fallback. In practice, tied operands with encodings that need
unification are uncommon.

I decide to not bail out the case in the first place because it'd add
much more complex to the implementation, while the fallback can be easy:
just add re-encode ops. It may result in the amount of memory footprint,
but it is a rare case.

It is a step towards https://github.com/iree-org/iree/issues/22485

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Signed-off-by: hanhanW <hanhan0912@gmail.com>