[K/N] Move kotlin.native.internal.Debugging into kotlin.native.runtime

As a part of efforts to stabilize Native stdlib #KT-55765.

kotlin-native/backend.native/tests/interop/cpp/skia.kt

@@ -11,7 +11,7 @@ fun main() {
 
     // TODO: the test used to work with forceCheckedShutdown,
     // but it is broken now. Revisit after it is fixed.
-    // kotlin.native.internal.Debugging.forceCheckedShutdown = true
+    // kotlin.native.runtime.Debugging.forceCheckedShutdown = true
     Platform.isCleanersLeakCheckerActive = true
 
     val f = Foo()