db: add test for chunks that span beyond a block's boundaries
db: add test for chunks that span beyond a block's boundaries

Signed-off-by: Benoît Knecht <2d06b2aecb2b450e75eada92208fcde4791c17df@fsfe.org>

GoogleCloudPlatform/prometheus,GoogleCloudPlatform/prometheus,Gouthamve/prometheus,kangwoo/prometheus,prometheus/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,alileza/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,prometheus/prometheus,alileza/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,alileza/prometheus,Gouthamve/prometheus,prometheus/tsdb,kangwoo/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,Gouthamve/tsdb,Gouthamve/prometheus,Gouthamve/prometheus,kangwoo/prometheus,keegancsmith/prometheus