add ignore_edge option in test list.

tests/selenium/javascript_unit_test_list.txt

Index: tests/selenium/javascript_unit_test_list.txt
===================================================================
--- tests/selenium/javascript_unit_test_list.txt	(revision 19792)
+++ tests/selenium/javascript_unit_test_list.txt	(working copy)
@@ -49,6 +49,12 @@
 #       environment(s) where the test should be skipped.
 #       Default = ""
 #
+#   pdiff_edge_ignore_off : Turn off edge detection function in pdiff. 
+#       By default, it's on with a default edge detect threshold 5.
+#
+#   pdiff_edge_threshold(0 to 7) : Set edge detect threshold in pdiff.
+#       This threshold indicates the max number of neighbors the pixel can
+#       have to be considered as edge. 0 means only ignore scattered pixels.
 # NOTE! ----------------------------------------------------------------------
 #
 # Read the sample guidelines
@@ -68,12 +74,12 @@
 small   quaternion-test
 small   base-test
 small   util-test
-small   pixel-perfection      screenshot pdiff_threshold(2500) pdiff_threshold_mac(3000) except(*iexplore)
+small   pixel-perfection      screenshot pdiff_threshold(200) pdiff_threshold_mac(3000) except(*iexplore)
 medium  offscreen-test
 medium  texture-set-test      screenshot
 medium  param-array-test      screenshot
 small   no-rendergraph        screenshot
-small   non-cachable-params   screenshot pdiff_threshold(1700)
+small   non-cachable-params   screenshot pdiff_threshold(200)
 small   type-test
 small   render-test
 # TODO Test disabled, as the behaviour on Chrome does not match other
@@ -90,4 +96,4 @@
 medium  TestStressDrawShapes   except(*googlechrome)
 medium  TestStressMultiWindow  except(*googlechrome)
 
-large   TestStressCullingZSort pdiff_threshold(14100)
+large   TestStressCullingZSort pdiff_threshold(200)