Merged requested to merge oda/athena:master-TRT_G4Utilities-v2 into master
- Add ATLAS_CHECK_THREAD_SAFETY to TRT_G4Utilities package.
- Add ATLAS_THREAD_SAFE to mutable Athena::MsgStreamMember m_msg.
- Add ATLAS_NOT_THREAD_SAFE to thread unsafe classes and methods and their clients including TRT_G4_SD package.
- Add ATLAS_NO_CHECK_FILE_THREAD_SAFETY to unit tests of TRT_G4Utilities and TRT_G4_SD packages.
- No result changes are expected.
- Related to https://its.cern.ch/jira/browse/ATLASRECTS-5560
- Replace messed-up and closed MR !34204 (closed)