AthenaKernel+AthenaServices, etc: Add IAthenaOutputTool::preStream()

Add abstract method IAthenaOutputTool::preStream(). To be called just before streaming objects. Call it from AthenaOutputStream. Clean up AthenaOutputStream a little bit.

added full-unit-tests label

This merge request affects 5 packages:

• Control/AthenaKernel
• Control/AthenaServices
• Database/AthenaPOOL/OutputStreamAthenaPool
• Database/AthenaRoot/AthenaRootComps
• Event/xAOD/xAODMetaDataCnv

Adding @akraszna ,@ssnyder ,@mnowak as watchers

added Core Database EDM JetEtmiss master review-pending-level-1 labels

CI Result FAILURE (hash ef04bf31)

	Athena	AthSimulation	AthGeneration
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 17594]

Jenkins please retry a build

This merge request affects 5 packages:

• Control/AthenaKernel
• Control/AthenaServices
• Database/AthenaPOOL/OutputStreamAthenaPool
• Database/AthenaRoot/AthenaRootComps
• Event/xAOD/xAODMetaDataCnv

Adding @akraszna ,@ssnyder ,@mnowak as watchers

CI Result FAILURE (hash ef04bf31)

	Athena	AthSimulation	AthGeneration
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 17720]

Looks OK. Test failures same as in nightlies.

Tadej (L2)

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 29bc0763

added sweep:ignore label