Cleanup of SCT_ReadoutTestAlg and addition of TestReadout (ATLASRECTS-4575)

Susumu Odarequested to merge
oda/athena:master-SCT_ReadoutTestAlg into master

Cleanup of SCT_ReadoutTestAlg and addition of TestReadout.

https://its.cern.ch/jira/browse/ATLASRECTS-4575

Merge request reports