Currently, we do not cap amount of tests returned to frontend,
thus in some extreme cases we can see a MBs of data stored in Redis.
This adds an upper limit of 100 tests per-suite.
We will continue showing the total counters correctly,
but we will limit amount of tests that will be presented.
It adds a base class for CompareTestReportsService
containing common code with CompareLicenseManagementReportsService
which is present in GitLab Enterprise Edition.