Add missing comma in list of strings

Bug: 1114873
Change-Id: Idc828b72f08583ab336c706c1bd8843e076bf573
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2357457Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799875}

ui/accessibility/platform/ax_platform_node_auralinux_unittest.cc

@@ -145,9 +145,7 @@ static void TestAtkObjectStringAttribute(
   EnsureAtkObjectDoesNotHaveAttribute(atk_object, attribute_name);
 
   const char* tests[] = {
-      "",
-      "a string with spaces"
-      "a string with , a comma",
+      "", "a string with spaces", "a string with , a comma",
       "\xE2\x98\xBA",  // The smiley emoji.
   };