Correctly processing inherited methods when checking for SAM interface.

compiler/testData/loadJava/compiledJava/singleAbstractMethod/SamSubinterfaceOfTwo.java

@@ -0,0 +1,14 @@
+package test;
+
+public interface SamSubinterfaceOfTwo {
+    public interface Super1 {
+        CharSequence f();
+    }
+
+    public interface Super2<T> {
+        T f();
+    }
+
+    public interface Sub extends Super1, Super2<String> {
+    }
+}