Revert "[TensorIR][Visitor] Visit buffer members in match_buffer's in block visitor functions (#15153)

[vinx13]

This reverts commit 34637d7.

It is better not visiting fields of buffer when visiting MatchBufferRegion since it's more common that the buffer is not mutated in StmtMutator (it can be left to the derived passes to handle case by case). It is also consistent with visitor/mutator for BufferLoad and BufferStore that do not visit buffer fields.
This fixes some broken tests in software pipelining where strides of some buffers in MatchBufferRegion are unintentionally mutated in-place.

cc @yzh119 @tqchen @junrushao

[yzh119]

I discussed with @vinx13 and I think it's reasonable not to visit buffers in the base mutator but explicitly do that in derived classes if necessary.

[Lunderberg]

As a potential third option, I think that we could have the buffers be visited at their point of definition. That is, any DeclBuffer statement would have the buffer internals visited once, and the mutated buffer would then be substituted in at all points of use. This would require the DeclBuffer to be present for all buffer objects, but that's part of the long-term plan anyways.