Safe Delete: Move test classes and test data to refactoring directory

idea/testData/refactoring/safeDelete/deleteFunction/javaFunctionWithKotlin/mixedHierarchy2.java

@@ -0,0 +1,10 @@
+interface A {
+    public void foo();
+}
+
+abstract class C implements B {
+    @Override
+    public void <caret>foo() {
+
+    }
+}