Remove property-specific handling in animation-test-helpers.js

LayoutTests/transitions/color-transition-premultiplied.html

Index: LayoutTests/transitions/color-transition-premultiplied.html
diff --git a/LayoutTests/transitions/color-transition-premultiplied.html b/LayoutTests/transitions/color-transition-premultiplied.html
index b8139f4f6e3c6b2b2055fde954df04d4fda56b68..65107bf3d2c8105d467eddc56d0ddab93b1d3cfc 100644
--- a/LayoutTests/transitions/color-transition-premultiplied.html
+++ b/LayoutTests/transitions/color-transition-premultiplied.html
@@ -33,8 +33,8 @@
   <script type="text/javascript">
     const expectedValues = [
       // [time, element-id, property, expected-value, tolerance]
-      [0.5, 'one', 'background-color', [0, 127, 0], 2],
-      [0.5, 'two', 'background-color', [0, 0, 255], 2]
+      [0.5, 'one', 'background-color', "rgba(0, 127, 0, 0.5)", 2],
+      [0.5, 'two', 'background-color', "rgba(0, 0, 255, 0.5)", 2]
     ];
 
     function setupTest()
@@ -58,4 +58,4 @@
   </div>
 
 </body>
-</html>
+</html>