jvm-abi-gen: Remove effectively private classes from ABI

#KT-64590 Fixed

plugins/jvm-abi-gen/testData/compile/conflictingClasses/app/app.kt

@@ -0,0 +1,5 @@
+package app
+
+//UnexpectedInnerClass although declared in a separate module
+//appear to be an inner class of the class generated from this file
+fun runAppAndReturnOk() = AppKt.UnexpectedInnerClass.result()

plugins/jvm-abi-gen/testData/compile/conflictingClasses/lib/AppKt.kt

@@ -0,0 +1,7 @@
+package app
+
+class AppKt {
+    object UnexpectedInnerClass {
+        fun result() = "OK"
+    }
+}