Remove extra comma in knownfailures.json

Test: testrunner.py --host
Change-Id: I4e374a419fa2fed19bbd1b86ce13f53c71d7b8bb
diff --git a/test/knownfailures.json b/test/knownfailures.json
index e03bd68..f6d82a7 100644
--- a/test/knownfailures.json
+++ b/test/knownfailures.json
@@ -356,5 +356,5 @@
         "description": ["Disable 638-checker-inline-caches temporarily until a fix",
                         "arrives."],
         "bug": "http://b/36371709"
-    },
+    }
 ]