KT-5287 J2K: Convert class with private constructor and static functions to "object" instead of class with "class object"

#KT-5287 Fixed

j2k/testData/fileOrElement/switch/fallDown.kt

@@ -1,16 +1,14 @@
 package switch_demo
 
-public class SwitchDemo {
-    companion object {
-        public fun main(args: Array<String>) {
-            val month = 8
-            val monthString: String
-            when (month) {
-                1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 -> monthString = "December"
-                else -> monthString = "Invalid month"
-            }
-            System.out.println(monthString)
+public object SwitchDemo {
+    public fun main(args: Array<String>) {
+        val month = 8
+        val monthString: String
+        when (month) {
+            1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 -> monthString = "December"
+            else -> monthString = "Invalid month"
         }
+        System.out.println(monthString)
     }
 }