extract class: allow to make nested (IDEA-144033)

java/java-tests/testData/refactoring/extractClass/innerClass/after/Test.java

@@ -0,0 +1,29 @@
+class Test {
+    final Extracted extracted = new Extracted(this);
+
+    void bar(){
+    System.out.println(extracted.getMyT());
+  }
+
+  String foo() {
+    return "";
+  }
+
+  void bazz() {
+    bar();
+  }
+
+    public static class Extracted {
+        private final Test test;
+        String myT;
+
+        public String getMyT() {
+            return myT;
+        }
+
+        public Extracted(Test test) {
+            this.test = test;
+            this.myT = test.foo();
+        }
+    }
+}

java/java-tests/testData/refactoring/extractClass/innerClass/before/Test.java

@@ -0,0 +1,15 @@
+class Test {
+  String myT = foo();
+
+  void bar(){
+    System.out.println(myT);
+  }
+
+  String foo() {
+    return "";
+  }
+
+  void bazz() {
+    bar();
+  }
+}