[VECGEOM-425]; Fixed warnings in CoaxialConeImplementation as reported by Gabriele,

               also enabled FPE in unit tests of GenericPolycone & CoaxialCones

[VECGEOM-425]; Minor bug fix in Extent function.

source/UnplacedGenericPolycone.cpp

@@ -68,7 +68,7 @@ void UnplacedGenericPolycone::Extent(Vector3D<Precision> &aMin, Vector3D<Precisi
    * written below can be used.
    */
   aMin.Set(-rmax, -rmax, fAMin.z());
-  aMin.Set(rmax, rmax, fAMax.z());
+  aMax.Set(rmax, rmax, fAMax.z());
   /*auto coneUnplaced = GeoManager::MakeInstance<UnplacedCone>(0., rmax, 0., rmax, 1., fSPhi, fDPhi);
   coneUnplaced->Extent(aMin, aMax);
   aMin.z() = fAMin.z();

test/unit_tests/TestCoaxialCones.cpp

@@ -10,7 +10,7 @@
 #include "volumes/EllipticUtilities.h"
 #include "volumes/CoaxialCones.h"
 #include "ApproxEqual.h"
-
+#include "base/FpeEnable.h"
 bool testvecgeom = false;
 
 using vecgeom::kInfLength;

test/unit_tests/TestGenericPolycone.cpp

@@ -13,7 +13,7 @@
 #include "ApproxEqual.h"
 #include "base/Vector.h"
 #include "volumes/GenericPolyconeStruct.h"
-
+#include "base/FpeEnable.h"
 bool testvecgeom = false;
 
 using vecgeom::kInfLength;

volumes/kernel/CoaxialConesImplementation.h

@@ -212,17 +212,6 @@ struct CoaxialConesImplementation {
       vecCore::MaskedAssign(safety, safeDist > safety, safeDist);
     }
   }
-
-  template <typename Real_v>
-  VECGEOM_FORCE_INLINE
-  VECCORE_ATT_HOST_DEVICE
-  static Vector3D<Real_v> NormalKernel(UnplacedStruct_t const &coaxialcones, Vector3D<Real_v> const &point,
-                                       typename vecCore::Mask_v<Real_v> &valid)
-  {
-    // Computes the normal on a surface and returns it as a unit vector
-    Vector3D<Real_v> normal(0., 0., 0.);
-    return normal;
-  }
 };
 } // namespace VECGEOM_IMPL_NAMESPACE
 } // namespace vecgeom