xAODCore, xAODCoreAthenaPool: Remove AuxSelection members.

Remove AuxSelection members from AuxInfoBase and AuxContainerBase. They're no longer used.

This merge request affects 2 packages:

• Event/xAOD/xAODCore
• Event/xAOD/xAODCoreAthenaPool

Adding @akraszna as watcher

added EDM master review-pending-level-1 labels

CI Result FAILURE (hash 02f094bd)

	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 19096]

Unrelated CI failure. Approving (L2 shifter)

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

merged

mentioned in commit 1f8f25ac

added sweep:ignore label