[mlir][tensor][bufferize] Reshapes: Fix memory side effects and memory space (#68195)

* `tensor.collapse_shape` may bufferize to a memory read because the op
may have to reallocate the source buffer.
* `tensor.reshape` should not use `bufferization.clone` for
reallocation. This op has requirements wrt. the order of buffer
writes/reads. Use `memref.alloc` and `memref.copy` instead. Also fix a
bug where the memory space of the source buffer was not propagated to
the reallocated buffer.