FPE: FLTINV and FLTDIV in Eigen::Spline interpolation

```
0# Eigen::internal::triangular_solve_matrix::run(long, long, double const*, long, double*, long, long, Eigen::internal::level3_blocking&) at /builds/acts/ci-bridge/dependencies/view/include/eigen3/Eigen/src/Core/products/TriangularSolverMatrix.h:124
1# void Eigen::HouseholderQR >::_solve_impl, Eigen::Matrix >(Eigen::Matrix const&, Eigen::Matrix&) const at /builds/acts/ci-bridge/dependencies/view/include/eigen3/Eigen/src/QR/HouseholderQR.h:371
2# void Eigen::internal::call_dense_assignment_loop, Eigen::Transpose >, Eigen::Matrix > const>, Eigen::internal::assign_op >(Eigen::Array&, Eigen::Transpose >, Eigen::Matrix > const> const&, Eigen::internal::assign_op const&) at /builds/acts/ci-bridge/dependencies/view/include/eigen3/Eigen/src/Core/AssignEvaluator.h:778
3# Eigen::Spline Eigen::SplineFitting >::Interpolate >(Eigen::Matrix const&, long, Eigen::Array const&) at /builds/acts/ci-bridge/dependencies/view/include/eigen3/unsupported/Eigen/src/Splines/SplineFitting.h:315
4# std::vector, std::allocator > > Acts::Interpolation3D::spline, std::allocator > > >(std::vector, std::allocator > > const&, unsigned long, bool) at /builds/acts/ci-bridge/src/Core/include/Acts/Visualization/Interpolation3D.hpp:62
5# ActsExamples::ObjSimHitWriter::writeT(ActsExamples::AlgorithmContext const&, boost::container::flat_multiset const&) at /builds/acts/ci-bridge/src/Examples/Io/Obj/src/ObjSimHitWriter.cpp:125
6# ActsExamples::Sequencer::run()::{lambda()#1}::operator()() const::{lambda(tbb::detail::d1::blocked_range const&)#1}::operator()(tbb::detail::d1::blocked_range const&) const at /builds/acts/ci-bridge/src/Examples/Framework/src/Framework/Sequencer.cpp:502
7# ActsExamples::Sequencer::run()::{lambda()#1}::operator()() const at /builds/acts/ci-bridge/src/Examples/Framework/src/Framework/Sequencer.cpp:463
```

@asalzburger could you look into this one?