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

src/IntWalk/IntWalk_PWalking.cdl

@@ -32,7 +32,8 @@ uses XY                  from gp,
      PntOn2S             from IntSurf,
      LineOn2S            from IntSurf,
      Dir                 from gp,
-     Dir2d               from gp
+     Dir2d               from gp,
+     Pnt                 from gp
      
      
 raises OutOfRange from Standard,
@@ -248,14 +249,36 @@ is
 	is static;
 
     AddAPoint ( me    : in out  ; 
-    	    	line  : in  out  LineOn2S  from  IntSurf  ;     
-		POn2S :          PntOn2S   from  IntSurf  ) ;
-	---C++: inline
-		
+    line  : in  out  LineOn2S  from  IntSurf  ;     
+    POn2S :          PntOn2S   from  IntSurf  ) ;
+    ---C++: inline
+    
     ExtendLineInCommonZone(me: in out; theChoixIso: ConstIsoparametric  from IntImp;
-    	    	    	    	       theDirectionFlag: Boolean from Standard)
-    	returns Boolean from Standard
-	is private;
+theDirectionFlag: Boolean from Standard)
+    returns Boolean from Standard
+    is private;
+  
+  DistanceMinimizeByGradient( me    : in out;
+                              theASurf1 , theASurf2  : ThePSurface ;
+                              theU1, theV1, theU2, theV2: out Real from Standard;
+                              theStep0U1V1: Real from Standard = 1.0e-6;
+                              theStep0U2V2: Real from Standard = 1.0e-6)
+    returns Boolean from Standard
+    is private;
+  
+  DistanceMinimizeByExtrema(me          : in out;
+                            theASurf1   : ThePSurface ;
+                            theP0       : Pnt from gp;
+                            theU0, theV0: out Real from Standard;
+                            theStep0U: Real from Standard = 1.0;
+                            theStep0V: Real from Standard = 1.0)
+    returns Boolean from Standard
+    is private;
+  
+  SeekAdditionalPoints( me    : in out;
+                        theASurf1 , theASurf2  : ThePSurface;
+                        theMinNbPoints : Integer from Standard)
+    returns Boolean from Standard;
 
 fields