This op used to belong to the sparse dialect, but there are use cases for dense bufferization as well. (E.g., when a tensor alloc is returned from a function and should be deallocated at the call site.) This change moves the op to the bufferization dialect, which now has an `alloc_tensor` and a `dealloc_tensor` op.
Differential Revision: https://reviews.llvm.org/D129985
Only the analysis part of the interface is implemented. The bufferization itself is performed by the SparseTensorConversion pass.
Differential Revision: https://reviews.llvm.org/D128138
