Single literal regexp value testcase for querier
Single literal regexp value testcase for querier

It's common to see queries like bar=~"foo" from machine generated
queries in the fronted. These are not evaluated as regexps, but are a
single-value-set, i.e. and equality matchings instead.

This is just a testcase for a single-value case.

Signed-off-by: Oleg Zaytsev <1d6e1cf70ec6f9ab28d3ea4b27a49a77654d370e@olegzaytsev.com>

GoogleCloudPlatform/prometheus,keegancsmith/prometheus,prometheus/prometheus,keegancsmith/prometheus,prometheus/prometheus,prometheus/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,prometheus/prometheus,alileza/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,alileza/prometheus,prometheus/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus