0027976: Unstable work of 2d intersection algorithm for two lines

1. Test case for the issue has been created.
The problem is still reproduced on MASTER.

2. Some test cases have been moved to lowalgos/2dinter grid.

tests/lowalgos/2dinter/bug24100

@@ -8,6 +8,7 @@ puts ""
 # Bad pcurve is built on a face while converting the shape from STEP format.
 ############################################################################
 
+pload XDE
 stepread [locate_data_file bug24100_REFLECT_CURVE_PART_5_SOL_ohne_Metadaten.stp] a *
 
 explode a_1 f

tests/lowalgos/2dinter/bug27976

@@ -0,0 +1,37 @@
+puts "========"
+puts "0027976: Unstable work of 2d intersection algorithm for two lines"
+puts "========"
+puts ""
+
+puts "TODO OCC27976 All: Error: wrong 2-th intersection result"
+
+set aRefPx 170.0
+set aRefPy 9620.0
+
+binrestore [locate_data_file bug27976_fe.bin] b
+explode b
+don b_1
+pcurve b_1
+
+smallview -2D-
+point p1 169.98949375765261 9619.9910661265931
+point p2 170.00862369283078 9620.0101960617721
+don p1 p2
+2dfit
+don b_1_4 b_1_5
+set log(1) [2dintersect b_1_4 b_1_5 -tol 1.e-10]
+checkview -screenshot -2d -path ${imagedir}/${test_image}_1.png
+
+trim c2d b_1_5 9610 9610.0000006891
+don b_1_4 c2d
+set log(2) [2dintersect b_1_4 c2d -tol 1.e-10]
+checkview -screenshot -2d -path ${imagedir}/${test_image}_2.png
+
+for {set i 1} {$i <= 2} {incr i} {
+  if { [regexp {Intersection point 1 : ([-0-9.+eE]+) ([-0-9.+eE]+)} $log($i) full cx($i) cy($i)] } {
+    set aDist($i) [2ddistpp $aRefPx $aRefPy $cx($i) $cy($i)]
+    checkreal Distance $aDist($i) 0.0 1.e-6 0.0
+  } else {
+    puts "Error: wrong $i-th intersection result"
+  }
+}