convert to instance/move instance: support default methods in interfaces for java 8 (IDEA-154833)

java/java-tests/testData/refactoring/convertToInstance8Method/InterfacePrivate.java.after

@@ -0,0 +1,22 @@
+interface I {
+    default void method(int i) {
+        System.out.println("i = " + i + ", intf = " + this);
+    }
+}
+
+interface J extends I {
+}
+
+class IImpl implements I {
+}
+
+class JImpl implements J {
+}
+
+class X {
+
+    {
+        J j = new JImpl();
+        j.method(0);
+    }
+}