fstream: add read-until-end tests without knowning the file size beforehand
fstream: add read-until-end tests without knowning the file size beforehand

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