PathLengthUtils: avoid tmp allocations. Rm cout
This started for removing temporary allocation due to use of dynamic (3,3) rather than fixed size (3,3) Eigen Matrices
71308 temporary allocations of 228458 allocations in total (74.98%) from
45296 Eigen::internal::aligned_malloc(unsigned long)
45297 at /cvmfs/sft.cern.ch/lcg/releases/eigen/3.3.7-642a5/x86_64-centos7-gcc11-opt/include/eigen3/Eigen/src/Core/util/Memory.h:159
45298 in /cvmfs/atlas-nightlies.cern.ch/repo/sw/master_Athena_x86_64-centos7-gcc11-opt/2023-01-31T2101/Athena/23.0.15/InstallArea/x86_64-centos7-gcc11-opt/lib/libTrackToCaloLib.so
45299 void* Eigen::internal::conditional_aligned_malloc<>(unsigned long)
45300 at /cvmfs/sft.cern.ch/lcg/releases/eigen/3.3.7-642a5/x86_64-centos7-gcc11-opt/include/eigen3/Eigen/src/Core/util/Memory.h:214
45301 double* Eigen::internal::conditional_aligned_new_auto<>(unsigned long)
45302 at /cvmfs/sft.cern.ch/lcg/releases/eigen/3.3.7-642a5/x86_64-centos7-gcc11-opt/include/eigen3/Eigen/src/Core/util/Memory.h:374
45303 Eigen::DenseStorage<>::resize(long, long, long)
45304 at /cvmfs/sft.cern.ch/lcg/releases/eigen/3.3.7-642a5/x86_64-centos7-gcc11-opt/include/eigen3/Eigen/src/Core/DenseStorage.h:408
45305 Eigen::PlainObjectBase<>::resize(long, long)
45306 at /cvmfs/sft.cern.ch/lcg/releases/eigen/3.3.7-642a5/x86_64-centos7-gcc11-opt/include/eigen3/Eigen/src/Core/PlainObjectBase.h:293
45307 void Eigen::PlainObjectBase<>::_init2<>(long, long, Eigen::internal::enable_if<>::type*)
45308 at /cvmfs/sft.cern.ch/lcg/releases/eigen/3.3.7-642a5/x86_64-centos7-gcc11-opt/include/eigen3/Eigen/src/Core/PlainObjectBase.h:743
45309 Eigen::Matrix<>::Matrix<>(int const&, int const&)
45310 at /cvmfs/sft.cern.ch/lcg/releases/eigen/3.3.7-642a5/x86_64-centos7-gcc11-opt/include/eigen3/Eigen/src/Core/Matrix.h:302
45311 PathLengthUtils::get3DPathLength(CaloCell const&, Eigen::Matrix<> const&, Eigen::Matrix<> const&, double, double)
45312 at /build/atnight/localbuilds/nightlies/Athena/master/athena/Reconstruction/RecoTools/TrackToCalo/src/PathLengthUtils.cxx:209
I noticed that the code had a custom "debug" (set locally at 0) and then a bunch of cout (if level > 1 or 2) which I removed...