Mismatch between expected and actual nonzeros when writing sparse to ultrasparse matrixblock

When writing a sparse to ultrasparse matrixblock in MatrixBlock.writeSparseToUltraSparse() an exception is thrown that indicates a mismatch in counted and expected nonzeros.

One quick solution is to add a recomputeNonzeros to the ReorgCPInstruction to keep the nonzeros up to date. I am not sure though if we want to do this after every reorg or if the mismatch comes from another place.