Fixed KT-4417 Converter from java to kotlin incorrectly places nested classes under class object

#KT-4417 Fixed

j2k/tests/testData/ast/class/innerEnum.java

@@ -0,0 +1,8 @@
+//file
+class A {
+    enum E {
+        A,
+        B,
+        C
+    }
+}