[Aria tests] Disable a flaky rule (AX_ARIA_08)

chrome/test/data/webui/test_api.js

Index: chrome/test/data/webui/test_api.js
diff --git a/chrome/test/data/webui/test_api.js b/chrome/test/data/webui/test_api.js
index a283c88bc536f23ae96c13e7b1ec8011c3b07f83..c089715f5644275848e890d3e42625bcad098dc9 100644
--- a/chrome/test/data/webui/test_api.js
+++ b/chrome/test/data/webui/test_api.js
@@ -211,6 +211,9 @@ var testing = {};
             // TODO(apacible): re-enable when following issue is fixed.
             // github.com/GoogleChrome/accessibility-developer-tools/issues/251
             "tableHasAppropriateHeaders",
+
+            // TODO(crbug.com/657514): This rule is flaky on Linux/ChromeOS.
+            "requiredOwnedAriaRoleMissing",
         ];
       }
       return this.accessibilityAuditConfig_;