0024472: Wrong section curves

0024472: Wrong section curves

1. Checking, if intersection curve is collapsed, is added. (file GeomInt_LineConstructor.cxx)
2. Earlier, intersection line was considered as valid if only mid-point of every interval of this line is into two intersected surfaces (with given tolerance). That's no good because after inserting of new points, old points, which is considered as valid only because they are into beginning or into end of interval (therefore, they was not checked), moved to mid of interval and became invalid. Therefore, checking for first and last points was added. (file GeomInt_LineConstructor.cxx)
3. Intersection line became valid (see bug description) after adding of new additional points into it (file IntPatch_PrmPrmIntersection.cxx). Methods for finding and adding of new points were added. (file IntWalk_PWalking_1.gxx)
Some test cases were changed.
Test cases for issue CR24472