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

java/java-tests/testData/refactoring/convertToInstance8Method/Interface3.java.after

@@ -0,0 +1,37 @@
+interface PsiAntElement {
+    default void m() {
+    }
+}
+
+interface AntElement extends PsiAntElement {
+}
+
+class AntElementImpl implements AntElement {
+}
+
+interface AntNameIdentifier extends AntElement {
+}
+
+class AntNameIdentifierImpl extends AntElementImpl implements AntNameIdentifier {
+}
+
+interface AntStructuredElement extends AntElement {
+}
+
+class AntStructuredElementImpl extends AntElementImpl implements AntStructuredElement {
+}
+
+interface AntTask extends AntStructuredElement {
+}
+
+class AntTaskImpl extends AntStructuredElementImpl implements AntTask {
+}
+
+interface AntMacroDef extends AntTask {
+}
+
+class AntMacroDefImpl extends AntTaskImpl implements AntMacroDef {
+}
+
+class X {
+}