ISF_HepMC_Tools: use common Gaudi GTest fixture
Use the common GTest Gaudi fixture instead of copy&paste. Added the missing toolSvc
accessor to the test fixture.
This also fixes a cppcheck defect on throwing in the destructor.
Use the common GTest Gaudi fixture instead of copy&paste. Added the missing toolSvc
accessor to the test fixture.
This also fixes a cppcheck defect on throwing in the destructor.