Check that fit succeeded and we actually have a track, before trying to print it.

Running with VERBOSE output in r07 I hit the following crash:

0x7f3d49abdd53 Trk::TrackInfo::dumpInfo[abi:cxx11]() const /build/atnight/localbuilds/nightlies/Athena/22.0/athena/Tracking/TrkEvent/TrkTrack/src/TrackInfo.cxx:52 + 0x203 [/cvmfs/atlas-nightlies.cern.ch/repo/sw/22.0_Athena_x86_64-centos7-gcc11-opt/2022-07-07T2101/Athena/22.0.75/InstallArea/x86_64-centos7-gcc11-opt/lib/libTrkTrack.so D[0x22d53]]
 0x7f3d49aba3b6 Trk::operator<<(MsgStream&, Trk::Track const&) /build/atnight/localbuilds/nightlies/Athena/22.0/athena/Tracking/TrkEvent/TrkTrack/src/Track.cxx:336 (discriminator 4) + 0x76 [/cvmfs/atlas-nightlies.cern.ch/repo/sw/22.0_Athena_x86_64-centos7-gcc11-opt/2022-07-07T2101/Athena/22.0.75/InstallArea/x86_64-centos7-gcc11-opt/lib/libTrkTrack.so D[0x1f3b6]]
 0x7f3d09ff4ce5 MsgStream::operator<<(MsgStream& (*)(MsgStream&)) /cvmfs/atlas-nightlies.cern.ch/repo/sw/22.0_Athena_x86_64-centos7-gcc11-opt/2022-07-06T2101/AthenaExternals/22.0.74/InstallArea/x86_64-centos7-gcc11-opt/include/GaudiKernel/MsgStream.h:134 (discriminator 5) + 0x565 [/home/emoyse/atlas/build/x86_64-centos7-gcc11-opt/lib/libMuonTrackSteeringTools.so D[0x14fce5]]
 0x7f3d0a00406b Muon::MooTrackFitter::fit(EventContext const&, Muon::MuPatCandidateBase const&, Muon::MuPatCandidateBase const&, std::vector<Trk::PrepRawData const*, std::allocator<Trk::PrepRawData const*> > const*) const /home/emoyse/atlas/athena/MuonSpectrometer/MuonReconstruction/MuonTrackMakers/MuonTrackMakerTools/MuonTrackSteeringTools/src/MooTrackFitter.cxx:236 + 0x70b [/home/emoyse/atlas/build/x86_64-centos7-gcc11-opt/lib/libMuonTrackSteeringTools.so D[0x15f06b]]
 0x7f3d09fcd38f Muon::MooTrackBuilder::combine(EventContext const&, Muon::MuPatCandidateBase const&, Muon::MuPatCandidateBase const&, std::vector<Trk::PrepRawData const*, std::allocator<Trk::PrepRawData const*> > const*) const /home/emoyse/atlas/athena/MuonSpectrometer/MuonReconstruction/MuonTrackMakers/MuonTrackMakerTools/MuonTrackSteeringTools/src/MooTrackBuilder.cxx:324 + 0x75f [/home/emoyse/atlas/build/x86_64-centos7-gcc11-opt/lib/libMuonTrackSteeringTools.so D[0x12838f]]
 0x7f3d09fce07c std::__uniq_ptr_impl<Trk::Track, std::default_delete<Trk::Track> >::_M_ptr() const /cvmfs/sft.cern.ch/lcg/releases/gcc/11.2.0-8a51a/x86_64-centos7/include/c++/11.2.0/bits/unique_ptr.h:173 + 0x2c [/home/emoyse/atlas/build/x86_64-centos7-gcc11-opt/lib/libMuonTrackSteeringTools.so D[0x12907c]]
 0x7f3d0a042cae Muon::MuonTrackSteering::combineOverlapSegments(EventContext const&, std::vector<Muon::MuPatSegment*, std::allocator<Muon::MuPatSegment*> >&, std::vector<Muon::MuPatSegment*, std::allocator<Muon::MuPatSegment*> >&, std::vector<std::vector<Muon::MuPatSegment*, std::allocator<Muon::MuPatSegment*> >, std::allocator<std::vector<Muon::MuPatSegment*, std::allocator<Muon::MuPatSegment*> > > >&, std::set<Muon::MuonStationIndex::StIndex, std::less<Muon::MuonStationIndex::StIndex>, std::allocator<Muon::MuonStationIndex::StIndex> >&, Muon::GarbageContainer&) const /home/emoyse/atlas/athena/MuonSpectrometer/MuonReconstruction/MuonTrackMakers/MuonTrackMakerTools/MuonTrackSteeringTools/src/MuonTrackSteering.cxx:233 + 0x36e [/home/emoyse/atlas/build/x86_64-centos7-gcc11-opt/lib/libMuonTrackSteeringTools.so D[0x19dcae]]
 0x7f3d0a0440c1 std::vector<std::vector<Muon::MuPatSegment*, std::allocator<Muon::MuPatSegment*> >, std::allocator<std::vector<Muon::MuPatSegment*, std::allocator<Muon::MuPatSegment*> > > >::operator[](unsigned long) /cvmfs/sft.cern.ch/lcg/releases/gcc/11.2.0-8a51a/x86_64-centos7/include/c++/11.2.0/bits/stl_vector.h:1046 + 0x431 [/home/emoyse/atlas/build/x86_64-centos7-gcc11-opt/lib/libMuonTrackSteeringTools.so D[0x19f0c1]]
 0x7f3d0a0492ad Muon::MuonTrackSteering::find(EventContext const&, std::vector<Muon::MuonSegment const*, std::allocator<Muon::MuonSegment const*> > const&) const /home/emoyse/atlas/athena/MuonSpectrometer/MuonReconstruction/MuonTrackMakers/MuonTrackMakerTools/MuonTrackSteeringTools/src/MuonTrackSteering.cxx:103 + 0x29d [/home/emoyse/atlas/build/x86_64-centos7-gcc11-opt/lib/libMuonTrackSteeringTools.so D[0x1a42ad]]
 0x7f3d21c263c8 std::__uniq_ptr_impl<DataVector<Trk::Track, DataModel_detail::NoBase>, std::default_delete<DataVector<Trk::Track, DataModel_detail::NoBase> > >::__uniq_ptr_impl(DataVector<Trk::Track, DataModel_detail::NoBase>*) /cvmfs/sft.cern.ch/lcg/releases/gcc/11.2.0-8a51a/x86_64-centos7/include/c++/11.2.0/bits/unique_ptr.h:155 + 0x2b8 [/home/emoyse/atlas/build/x86_64-centos7-gcc11-opt/lib/libMuonSegmentTrackMaker.so D[0x403c8]]
 0x7f3d501433f7 Gaudi::Algorithm::sysExecute(EventContext const&) /build/atnight/localbuilds/nightlies/Athena/22.0/build/build/AthenaExternals/src/Gaudi/GaudiKernel/src/Lib/Algorithm.cpp:366 + 0x1a7 [/cvmfs/atlas-nightlies.cern.ch/repo/sw/22.0_Athena_x86_64-centos7-gcc11-opt/2022-07-06T2101/AthenaExternals/22.0.74/InstallArea/x86_64-centos7-gcc11-opt/lib/libGaudiKernel.so D[0x2323f7]]

This MR should fix it - basically, we cannot print a track we don't have, so check if the fit failed before trying to dump it.

Tested with q445 locally.

This will not change output in any way.