TRT_RawDataByteStreamCnv: threading fixes

Rework to avoid calling naughtyRetrieve.

Remove ATLAS_NOT_THREAD_SAFE annotations --- just need to avoid a (needless!) AttributeList copy.

Make sure to protect TRTRawDataProviderTool::m_cache with a lock. Not safe to omit it.

Note that the original code was sometimes unpacking the same channel multiple times into the same collection. This behavior is fixed by the change, but it results in RootComp differences for a couple TriggerTest ART tests.

InnerDetector/InDetEventCnv/TRT_RawDataByteStreamCnv/src/TRTRawDataProviderTool.cxx

@@ -99,9 +99,7 @@ StatusCode TRTRawDataProviderTool::convert(const std::vector<const ROBFragment*>
   std::vector<const ROBFragment*>::const_iterator rob_it = vecRobs.begin();
 
   const EventContext& ctx{Gaudi::Hive::currentContext()};
-  //  std::lock_guard<std::mutex> lock{m_mutex};
-  // Do not lock mutex because this convert method is non-const.
-  // But we should make this method const.
+  std::lock_guard<std::mutex> lock{m_mutex};
   CacheEntry* ent{m_cache.get(ctx)};
   if (ent->m_evt!=ctx.evt()) { // New event in this slot
     ent->m_LastLvl1ID = 0xffffffff;