[K/N] keep internal members in header klibs

This is also the behavior of jvm-abi-gen and desired to support
friend modules.
^KT-65442

native/native.tests/testData/klib/header-klibs/comparison/syntheticAccessors/base/test.kt

@@ -4,4 +4,4 @@ private val x = 1
 
 object A { fun f() = x }
 
-val y = 2
+val y = (0..20).random()

native/native.tests/testData/klib/header-klibs/comparison/syntheticAccessors/sameAbi/test.kt

@@ -2,4 +2,4 @@ package test
 
 object A { fun f() = 1 }
 
-val y = 2
+val y = (30..50).random()