Add xAOD::getOriginalObjectLink(...), master branch (2020.11.05.)

Added the xAOD::getOriginalObjectLink(...) function. To help reconstruction code with using such links, as we discussed with @khoo and @xiaozhon on the offlineSWHelp list.

This merge request affects 3 files:

• Event/xAOD/xAODBase/CMakeLists.txt
• Event/xAOD/xAODBase/Root/IParticleHelpers.cxx
• Event/xAOD/xAODBase/xAODBase/IParticleHelpers.h

Adding @akraszna as watcher

added EDM master review-pending-level-1 labels

CI Result SUCCESS (hash 95b5fbe0)

	Athena	AthSimulation	AthGeneration	AnalysisBase
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
AnalysisBase: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 22997]

MR looks good. Approving (L1)

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

merged

mentioned in commit 107e70e6

added sweep:ignore label