adjust mapbox_angles compare test

Author: archmoj

test/image/compare_pixels_test.js

@@ -124,7 +124,11 @@ for(var i = 0; i < allMockList.length; i++) {
 
     var numDiffPixels = pixelmatch(img0.data, img1.data, diff.data, width, height, {
         threshold: shouldBePixelPerfect ? 0 :
-            mockName === 'mapbox_geojson-attributes' ? 0.25 : 0.15
+            [
+                // more flaky
+                'mapbox_angles',
+                'mapbox_geojson-attributes'
+            ].indexOf(mockName) !== -1 ? 0.25 : 0.15
     });
 
     if(numDiffPixels) {