FastCaloSimAthenaPool: cmake fixes

Don't build the same sources into more than one library.

This merge request affects 1 package:

• Simulation/FastShower/FastCaloSimAthenaPool

Adding @jchapman ,@vpascuzz as watchers

added Simulation master review-pending-level-1 labels

enabled an automatic merge when the pipeline for fc20d09e succeeds

CI Result SUCCESS (hash fc20d09e)

	Athena	AthSimulation	AnalysisBase	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
AnalysisBase: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 13388]

merged

mentioned in commit 6918bc53

added sweep:ignore label