Remove --supermixin flag from VM.

tests/co19/co19-co19.status

Index: tests/co19/co19-co19.status
diff --git a/tests/co19/co19-co19.status b/tests/co19/co19-co19.status
index 2e60ccca27cf13330af5616b9bc187388915d10b..c28d8d8930a0176c9fceef79d2906eb6945325c1 100644
--- a/tests/co19/co19-co19.status
+++ b/tests/co19/co19-co19.status
@@ -4,7 +4,8 @@
 
 # This file contains the tests that have been identified as broken and
 # have been filed on the co19 issue tracker at
-#    https://code.google.com/p/co19/issues/list .
+#    https://code.google.com/p/co19/issues/list (read-only).
+#    https://github.com/dart-lang/co19/issues .
 #
 # In order to qualify here these tests need to fail both on the VM and dart2js.
 
@@ -13,6 +14,10 @@
 [ $runtime == vm || $runtime != vm ]
 # Tests that fail everywhere, including the analyzer.
 
+# Super is now allowed in mixins and mixins may now extend a subclass of Object.
+Language/09_Mixins/09_Mixins_A01_t01: Skip # co19 issue 9.
+Language/09_Mixins/09_Mixins_A03_t01: Skip # co19 issue 9.
+
 # No longer correct, y#$ now has a meaning. github.com/dart-lang/co19/issues/2
 Language/12_Expressions/30_Identifier_Reference_A01_t03: Skip