tests: Add cql_test_env::require_column_has_value()
tests: Add cql_test_env::require_column_has_value()

Copied from cql_query_test.cc.

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