Add mutex to guard a mutable member in TrackSelectionTool

http://goetz.web.cern.ch/goetz/mutable_2019-07-13.html#InnerDetector_Other

nightly/master/2019-07-13T2149:InnerDetector/InDetRecTools/InDetTrackSelectionTool/InDetTrackSelectionTool/InDetTrackSelectionTool.h +105
431c67b9926b18705c43e580bc691082460d6006	2019-06-06_T1140	Susumu Oda	Partially fix thread-safe issues of InDetTrackSelectionTool

   103	    mutable std::atomic<ULong64_t> m_numTracksProcessed = 0; //!< a counter of the number of tracks proccessed
   104	    mutable std::atomic<ULong64_t> m_numTracksPassed = 0; //!< a counter of the number of tracks that passed all cuts
   105	    mutable std::vector<ULong64_t> m_numTracksPassedCuts; //!< tracks the number of tracks that passed each cut family
   106	
   107	    constexpr static Double_t LOCAL_MAX_DOUBLE = 1.0e16;