Make SiSpacePointsSeedTool_xk thread-safe (ATLASRECTS-3037)

* mapOneSeeds
mapOneSeeds     ['std::multimap<float,InDet::SiSpacePointsSeed*>', 4]
mapOneSeeds_Pro ['std::multimap<float,InDet::SiSpacePointsProSeed*>', 1]
mapOneSeeds_ITK ['std::multimap<float,InDet::SiSpacePointsProSeedITK*>', 1]

* OneSeeds
OneSeeds     ['std::vector<InDet::SiSpacePointsSeed>', 4]
OneSeeds_Pro ['std::vector<InDet::SiSpacePointsProSeed>', 1]
OneSeeds_ITK ['std::vector<InDet::SiSpacePointsProSeedITK>', 1]

* l_seeds
l_seeds     ['std::list<InDet::SiSpacePointsSeed>', 4]
l_seeds_Pro ['std::list<InDet::SiSpacePointsProSeed>', 1]
l_seeds_ITK ['std::list<InDet::SiSpacePointsProSeedITK>', 1]
l_seeds_map ['std::multimap<float,InDet::SiSpacePointsSeed*>', 1]

* i_seed
i_seed     ['std::list<InDet::SiSpacePointsSeed>::iterator', 4]
i_seed_Pro ['std::list<InDet::SiSpacePointsProSeed>::iterator', 1]
i_seed_ITK ['std::list<InDet::SiSpacePointsProSeedITK>::iterator', 1]
i_seed_map ['std::multimap<float,InDet::SiSpacePointsSeed*>::iterator', 1]

* i_seede
i_seede     ['std::list<InDet::SiSpacePointsSeed>::iterator', 4]
i_seede_Pro ['std::list<InDet::SiSpacePointsProSeed>::iterator', 1]
i_seede_ITK ['std::list<InDet::SiSpacePointsProSeedITK>::iterator', 1]
i_seede_map ['std::multimap<float,InDet::SiSpacePointsSeed*>::iterator', 1]

* seeds
seeds     ['std::vector<InDet::SiSpacePointsSeed>', 1]
seeds_Pro ['std::multimap<float,InDet::SiSpacePointsProSeed*>', 1]
seeds_ITK ['std::multimap<float,InDet::SiSpacePointsProSeedITK*>', 1]

* seed
seed     ['std::multimap<float,InDet::SiSpacePointsSeed*>::iterator', 1]
seed_Pro ['std::multimap<float,InDet::SiSpacePointsProSeed*>::iterator', 1]
seed_ITK ['std::multimap<float,InDet::SiSpacePointsProSeedITK*>::iterator', 1]