[canvaskit] Fix arc() call

Bug: skia:
Change-Id: I7a06b4bd5d2e88b12b08b0568301515653512ebb
Reviewed-on: https://skia-review.googlesource.com/c/173236
Reviewed-by: Kevin Lubick <kjlubick@google.com>

experimental/canvaskit/htmlcanvas/canvas2d.js

@@ -6,7 +6,7 @@
 
   function allAreFinite(args) {
     for (var i = 0; i < args.length; i++) {
-      if (!Number.isFinite(args[i])) {
+      if (args[i] !== undefined && !Number.isFinite(args[i])) {
         return false;
       }
     }