Add benchmark for Querier.Select over blocks and head.
Add benchmark for Querier.Select over blocks and head.

Signed-off-by: Brian Brazil <aadf89994a343dc176a47081f0c0bbea26f0a345@robustperception.io>

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