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/function/main.kt

@@ -1,4 +1,2 @@
-companion object {
-    public fun main(args: Array<String>) {
-    }
+public fun main(args: Array<String>) {
 }