[fixes #3370] Support Helper in method

test/transform/resource/after-delombok/HelperInMethod.java

@@ -0,0 +1,13 @@
+public class HelperInMethod {
+	int someMethod(int arg1) {
+		int localVar = 5;
+
+		class Helpers {
+			int helperMethod(int arg) {
+				return arg + localVar;
+			}
+		}
+		final Helpers $Helpers = new Helpers();
+		return $Helpers.helperMethod(10);
+	}
+}