Fix vtable corruption.

Due to failing to keep track of superclass implementations of
interface methods we could end up in situations where methods were
placed onto a class's vtable multiple times. This could cause virtual
and interface dispatches on subclasses to fail by causing corruption
of the subclass's vtable and iftable.

Bug: 28333278

Change-Id: I37d9740ca912daf37cdf9ff82697bbc5db46177a
diff --git a/test/960-default-smali/src/Foo.java b/test/960-default-smali/src/Foo.java
new file mode 100644
index 0000000..ed5b35f
--- /dev/null
+++ b/test/960-default-smali/src/Foo.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+interface Foo {
+  public default String bar() {
+    return "foobar";
+  }
+}