Add new test to failure list where appropriate.
diff --git a/conformance/failure_list_php.txt b/conformance/failure_list_php.txt
index d51a75d..667f80c 100644
--- a/conformance/failure_list_php.txt
+++ b/conformance/failure_list_php.txt
@@ -13,6 +13,8 @@
 Required.Proto3.JsonInput.Int32FieldNotInteger
 Required.Proto3.JsonInput.Int64FieldNotInteger
 Required.Proto3.JsonInput.OneofFieldDuplicate
+Required.Proto3.JsonInput.OneofFieldNullSecond.JsonOutput
+Required.Proto3.JsonInput.OneofFieldNullSecond.ProtobufOutput
 Required.Proto3.JsonInput.RepeatedFieldWrongElementTypeExpectingStringsGotInt
 Required.Proto3.JsonInput.RepeatedListValue.JsonOutput
 Required.Proto3.JsonInput.RepeatedListValue.ProtobufOutput