Remove visual test tolerances for files that are now deterministic

With the fixed-seed RNG, koch.ps, fern.ps, hugofrac.ps, and
manylines.ps produce identical output every run and no longer
need per-file diff tolerances.

Author: AndyCappDev

visual_tests_pdf.conf

@@ -11,12 +11,8 @@
 #   random_dither.ps  100    # Fully random output, just check it renders
 #   partial_random.ps 25     # Partially random, allow up to 25% diff
 
-koch.ps 0.30
 eyechart.ps 7
-fern.ps 8
-hugofrac.ps 15
-manylines.ps 0.11
 maze.ps 7
-snowflak.ps 95
-ppst32.ps 0.15
 ppd_info.ps 0.05
+ppst32.ps 0.15
+snowflak.ps 95

visual_tests_png.conf

@@ -11,12 +11,8 @@
 #   random_dither.ps  100    # Fully random output, just check it renders
 #   partial_random.ps 25     # Partially random, allow up to 25% diff
 
-koch.ps 0.30
 eyechart.ps 7
-fern.ps 8
-hugofrac.ps 15
-manylines.ps 0.11
 maze.ps 7
-snowflak.ps 95
-ppst32.ps 0.15
 ppd_info.ps 0.05
+ppst32.ps 0.15
+snowflak.ps 95

visual_tests_svg.conf

@@ -11,12 +11,8 @@
 #   random_dither.ps  100    # Fully random output, just check it renders
 #   partial_random.ps 25     # Partially random, allow up to 25% diff
 
-koch.ps 0.30
 eyechart.ps 7
-fern.ps 8
-hugofrac.ps 15
-manylines.ps 0.11
 maze.ps 7
-snowflak.ps 95
-ppst32.ps 0.15
 ppd_info.ps 0.05
+ppst32.ps 0.15
+snowflak.ps 95