0028681: UnifySameDomain distorts face boundary when merges a chain of small linear edges

In case of sequence of edges based on lines (which are going to be unified into one line-segment), take into account a linear tolerance  value.
Get rid of regressions.
Updates of USD-tests.

tests/bugs/modalg_6/bug28207

@@ -9,12 +9,34 @@ puts ""
 restore [locate_data_file bug28207_face.brep] s1
 
 unifysamedom result1 s1
+checkshape result1
 checknbshapes result1 -face 1 -wire 1 -edge 984
+checkprops result1 -l 10402.1
 
+#safeInputMode is true for USD
 unifysamedom result2 s1 -a 0.001
-checknbshapes result2 -face 1 -wire 1 -edge 223
+checkshape result2
+checknbshapes result2 -face 1 -wire 1 -edge 983
+checkprops result2 -l 10402.1
 
-unifysamedom result s1 -a 1.0
-checknbshapes result -face 1 -wire 1 -edge 4
+unifysamedom result3 s1 -a 1.0
+checkshape result3
+checknbshapes result3 -face 1 -wire 1 -edge 983
+checkprops result3 -l 10402.1
 
-checkview -display result -2d -path ${imagedir}/${test_image}.png
+unifysamedom result4 s1 -t 0.01 -a 0.1
+checkshape result4
+checknbshapes result4 -face 1 -wire 1 -edge 510
+checkprops result4 -l 10402.1
+
+unifysamedom result5 s1 -t 0.1 -a 0.1
+checkshape result5
+checknbshapes result5 -face 1 -wire 1 -edge 198
+checkprops result5 -l 10402.1
+
+unifysamedom result6 s1 -t 1.0 -a 0.1
+checkshape result6
+checknbshapes result6 -face 1 -wire 1 -edge 65
+checkprops result6 -l 10401.9
+
+checkview -display result1 -2d -path ${imagedir}/${test_image}.png

tests/bugs/modalg_7/bug27004

@@ -24,7 +24,7 @@ unifysamedom result r
 
 checkshape result
 
-checknbshapes result -vertex 12 -edge 18 -wire 8 -face 8 -solid 1
+checknbshapes result -vertex 16 -edge 22 -wire 8 -face 8 -solid 1
 checkprops result -s 223704 -v 3.27888e+006
 
 checkview -display result -2d -path ${imagedir}/${test_image}.png