mutation_partition: add function to return a reference to _rows
mutation_partition: add function to return a reference to _rows

Signed-off-by: Raphael S. Carvalho <1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@cloudius-systems.com>
Reviewed-by: Nadav Har'El <625169824b719df98706d88646d0aae6f368ae4d@cloudius-systems.com>

dwdm/scylla,glommer/scylla,kjniemi/scylla,phonkee/scylla,avikivity/scylla,victorbriz/scylla,tempbottle/scylla,kjniemi/scylla,kjniemi/scylla,justintung/scylla,duarten/scylla,raphaelsc/scylla,wildinto/scylla,stamhe/scylla,capturePointer/scylla,wildinto/scylla,rentongzhang/scylla,shaunstanislaus/scylla,justintung/scylla,avikivity/scylla,linearregression/scylla,respu/scylla,acbellini/scylla,senseb/scylla,capturePointer/scylla,senseb/scylla,gwicke/scylla,tempbottle/scylla,victorbriz/scylla,bowlofstew/scylla,aruanruan/scylla,gwicke/scylla,shaunstanislaus/scylla,rentongzhang/scylla,aruanruan/scylla,respu/scylla,dwdm/scylla,justintung/scylla,scylladb/scylla,kangkot/scylla,shaunstanislaus/scylla,scylladb/scylla,stamhe/scylla,scylladb/scylla,glommer/scylla,kangkot/scylla,stamhe/scylla,eklitzke/scylla,glommer/scylla,duarten/scylla,asias/scylla,rentongzhang/scylla,avikivity/scylla,raphaelsc/scylla,raphaelsc/scylla,kangkot/scylla,capturePointer/scylla,guiquanz/scylla,bowlofstew/scylla,phonkee/scylla,rluta/scylla,linearregression/scylla,eklitzke/scylla,asias/scylla,acbellini/scylla,acbellini/scylla,asias/scylla,guiquanz/scylla,dwdm/scylla,eklitzke/scylla,rluta/scylla,victorbriz/scylla,tempbottle/scylla,aruanruan/scylla,linearregression/scylla,rluta/scylla,senseb/scylla,guiquanz/scylla,wildinto/scylla,respu/scylla,bowlofstew/scylla,scylladb/scylla,duarten/scylla,gwicke/scylla,phonkee/scylla