test case for Coherence modifying the transfinite attributes

benchmarks/2d/transfinite_coherence.geo

+
+
+Function Square
+
+p1 = newp ; Point (p1) = {   X0,   Y0, Z0, LC } ;
+p2 = newp ; Point (p2) = { X0+c,   Y0, Z0, LC } ;
+p3 = newp ; Point (p3) = { X0+c, Y0+c, Z0, LC } ;
+p4 = newp ; Point (p4) = {   X0, Y0+c, Z0, LC } ;
+
+l1 = newl ; Line (l1) = { p1, p2 } ;
+l2 = newl ; Line (l2) = { p2, p3 } ;
+l3 = newl ; Line (l3) = { p3, p4 } ;
+l4 = newl ; Line (l4) = { p4, p1 } ;
+
+Transfinite Line { l1, l2, l3, l4 } = D ;
+
+ll = newl ; Line Loop (ll) = { l1, l2, l3, l4 } ;
+ns = news ; Plane Surface (ns) = { ll } ;
+Transfinite Surface { ns } = { p1, p2, p3, p4 } ;
+Recombine Surface { ns } ;
+
+LS[iLS] = ns ; iLS += 1 ;
+
+Return
+
+
+LS[] = { 0 } ; iLS = 0 ;
+
+c  = 1.0 ;
+LC = 0.1 ;
+D  = 11 ;
+
+X0 = 0 ; Y0 = 0 ; Z0 = 0 ; 
+
+Call Square ;
+
+X0 += c ;
+Call Square ;
+
+Coherence ;
+
+Physical Surface (100) = LS[] ;
+