[mlir][bufferization] Add lowering of bufferization.dealloc to memref.dealloc

Adds a generic lowering that suppors all cases of bufferization.dealloc
and one specialized, more efficient lowering for the simple case. Using
a helper function with for loops in the general case enables
O(|num_dealloc_memrefs|+|num_retain_memrefs|) size of the lowered code.

Depends on D155467

Reviewed By: springerm

Differential Revision: https://reviews.llvm.org/D155468