tests: memcache: add tests for 'noreply' variant of 'set' and 'delete'
tests: memcache: add tests for 'noreply' variant of 'set' and 'delete'

This also extracts some code to a common base class.

flashbuckets/seastar,kjniemi/scylla,respu/scylla,sjperkins/seastar,justintung/scylla,scylladb/scylla-seastar,shaunstanislaus/scylla,acbellini/seastar,bowlofstew/seastar,flashbuckets/seastar,stamhe/scylla,eklitzke/scylla,dwdm/seastar,joerg84/seastar,acbellini/seastar,glommer/scylla,phonkee/scylla,wildinto/seastar,scylladb/scylla,aruanruan/scylla,duarten/scylla,dwdm/scylla,wildinto/scylla,kjniemi/scylla,dreamsxin/seastar,sjperkins/seastar,raphaelsc/scylla,dreamsxin/seastar,rluta/scylla,norcimo5/seastar,raphaelsc/seastar,senseb/scylla,wildinto/scylla,duarten/scylla,shyamalschandra/seastar,xtao/seastar,scylladb/seastar,capturePointer/scylla,rluta/scylla,acbellini/scylla,rentongzhang/scylla,duarten/scylla,wildinto/seastar,acbellini/scylla,xtao/seastar,chunshengster/seastar,tempbottle/scylla,bowlofstew/scylla,avikivity/scylla,cloudius-systems/seastar,leejir/seastar,aruanruan/scylla,justintung/scylla,scylladb/scylla-seastar,ducthangho/imdb,raphaelsc/seastar,tempbottle/seastar,raphaelsc/scylla,tempbottle/scylla,asias/scylla,shaunstanislaus/scylla,avikivity/scylla,rentongzhang/scylla,jonathanleang/seastar,dwdm/scylla,mixja/seastar,rluta/scylla,avikivity/seastar,scylladb/scylla,gwicke/scylla,acbellini/scylla,shyamalschandra/seastar,anzihenry/seastar,xtao/seastar,dwdm/scylla,bowlofstew/seastar,joerg84/seastar,norcimo5/seastar,kangkot/scylla,koolhazz/seastar,koolhazz/seastar,asias/scylla,jonathanleang/seastar,slivne/seastar,dwdm/seastar,scylladb/seastar,chunshengster/seastar,linearregression/seastar,acbellini/seastar,leejir/seastar,tempbottle/seastar,guiquanz/scylla,stamhe/seastar,hongliangzhao/seastar,flashbuckets/seastar,raphaelsc/scylla,ducthangho/imdb,victorbriz/scylla,kjniemi/scylla,bzero/seastar,victorbriz/scylla,kangkot/scylla,shyamalschandra/seastar,tempbottle/scylla,kjniemi/seastar,sjperkins/seastar,dwdm/seastar,victorbriz/scylla,bzero/seastar,bowlofstew/scylla,ducthangho/imdb,scylladb/scylla,asias/scylla,norcimo5/seastar,glommer/scylla,avikivity/scylla,tempbottle/seastar,anzihenry/seastar,linearregression/seastar,syuu1228/seastar,linearregression/scylla,linearregression/seastar,printedheart/seastar,avikivity/seastar,scylladb/scylla-seastar,phonkee/scylla,chunshengster/seastar,hongliangzhao/seastar,bzero/seastar,anzihenry/seastar,slivne/seastar,stamhe/scylla,printedheart/seastar,wildinto/scylla,bowlofstew/scylla,syuu1228/seastar,eklitzke/scylla,linearregression/scylla,leejir/seastar,gwicke/scylla,senseb/scylla,dreamsxin/seastar,respu/scylla,cloudius-systems/seastar,scylladb/scylla,mixja/seastar,glommer/scylla,printedheart/seastar,guiquanz/scylla,eklitzke/scylla,stamhe/seastar,capturePointer/scylla,cloudius-systems/seastar,guiquanz/scylla,kjniemi/seastar,mixja/seastar,stamhe/seastar,raphaelsc/seastar,phonkee/scylla,scylladb/seastar,justintung/scylla,aruanruan/scylla,joerg84/seastar,jonathanleang/seastar,kjniemi/seastar,bowlofstew/seastar,slivne/seastar,linearregression/scylla,stamhe/scylla,gwicke/scylla,syuu1228/seastar,kangkot/scylla,rentongzhang/scylla,avikivity/seastar,wildinto/seastar,capturePointer/scylla,senseb/scylla,shaunstanislaus/scylla,respu/scylla,koolhazz/seastar,hongliangzhao/seastar