Fix for on surface and moving out condition for grazing rays on sphere.

DistanceToOut for sphere returned kInfLength for rays starting from surface and having the direction almost perpendicular to the position vector, but slightly inwards. Such rays were supposed to give a crossing solution for intersecting the outer surface, but numerically did not in case the surface point is close to rmax+kTolerance. This fixes such problems, and also the G4+VecGeom dna example test.

VecGeom/base/Math.h

@@ -17,12 +17,14 @@ inline namespace VECGEOM_IMPL_NAMESPACE {
 #ifdef VECGEOM_FLOAT_PRECISION
 using Precision                        = float;
 VECGEOM_CONST Precision kTolerance     = 1e-3;
+VECGEOM_CONST Precision kSqrtTolerance = 3.1622777e-2;
 VECGEOM_CONST Precision kAngTolerance  = 1e-2;
 VECGEOM_CONST Precision kConeTolerance = 1e-3;
 VECGEOM_CONST Precision kFarAway       = 1e5;
 #else
 using Precision                        = double;
 VECGEOM_CONST Precision kTolerance     = 1e-9;
+VECGEOM_CONST Precision kSqrtTolerance = 3.1622777e-5;
 VECGEOM_CONST Precision kAngTolerance  = 1e-9;
 VECGEOM_CONST Precision kConeTolerance = 1e-7;
 VECGEOM_CONST Precision kFarAway       = 1e10;