Add a scale down by 3 test for testing general purpose box/bilinear with scale…

Add a scale down by 3 test for testing general purpose box/bilinear with scale factor of 3, but allowing width/height specified to do odd with testing.
BUG=libyuv:427
TESTED=libyuvTest.ScaleDownBy3*
R=bcornell@google.com

Review URL: https://webrtc-codereview.appspot.com/45169004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1370 16f28f9a-4ce2-e073-06de-1de4eb20be90

unit_test/scale_argb_test.cc

@@ -226,6 +226,7 @@ TEST_FACTOR(4, 1 / 4, 1 / 4)
 TEST_FACTOR(8, 1 / 8, 1 / 8)
 TEST_FACTOR(3by4, 3 / 4, 3 / 4)
 TEST_FACTOR(3by8, 3 / 8, 3 / 8)
+TEST_FACTOR(3, 1 / 3, 1 / 3)
 #undef TEST_FACTOR1
 #undef TEST_FACTOR
 

unit_test/scale_test.cc

@@ -290,6 +290,7 @@ TEST_FACTOR(4, 1 / 4, 1 / 4)
 TEST_FACTOR(8, 1 / 8, 1 / 8)
 TEST_FACTOR(3by4, 3 / 4, 3 / 4)
 TEST_FACTOR(3by8, 3 / 8, 3 / 8)
+TEST_FACTOR(3, 1 / 3, 1 / 3)
 #undef TEST_FACTOR1
 #undef TEST_FACTOR