scrape: Move tests to testutil (#6187)
scrape: Move tests to testutil (#6187)

Part of the fix for #3242.

Signed-off-by: Alex Dzyoba <60c6d277a8bd81de7fdde19201bf9c58a3df08f4@dzyoba.com>
keegancsmith/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,kangwoo/prometheus,kangwoo/prometheus,Gouthamve/prometheus,keegancsmith/prometheus,Gouthamve/prometheus,prometheus/prometheus,prometheus/prometheus,prometheus/prometheus,Gouthamve/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,kangwoo/prometheus,keegancsmith/prometheus,Gouthamve/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,alileza/prometheus,keegancsmith/prometheus,kangwoo/prometheus,keegancsmith/prometheus,prometheus/prometheus,alileza/prometheus