[mlir][Vector] Tighten up application conditions in TransferReadAfter… (#143869)

…WriteToBroadcast

The pattern would previously apply in spurious cases and generate
incorrect IR.

In the process, we disable the application of this pattern in the case
where there is no broadcast; this should be handled separately and may
more easily support masking.

The case {no-broadcast, yes-transpose} was previously caught by this
pattern and arguably could also generate incorrect IR (and was also
untested): this case does not apply anymore.

The last cast {yes-broadcast, yes-transpose} continues to apply but
should arguably be removed from the future because creating transposes
as part of canonicalization feels dangerous.
There are other patterns that move permutation logic:

- either into the transfer, or
- outside of the transfer

Ideally, this would be target-dependent and not a canonicalization (i.e.
does your DMA HW allow transpose on the fly or not) but this is beyond
the scope of this PR.

Co-authored-by: Nicolas Vasilache <nicolasvasilache@users.noreply.github.com>

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