tests: add test for bug in error propagation by future::then()
tests: add test for bug in error propagation by future::then()

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