Mark special internal scripts as native scripts

test/mjsunit/debug-script.js

Index: test/mjsunit/debug-script.js
===================================================================
--- test/mjsunit/debug-script.js	(revision 1441)
+++ test/mjsunit/debug-script.js	(working copy)
@@ -54,7 +54,7 @@
 }
 
 // This has to be updated if the number of native scripts change.
-assertEquals(12, native_count);
+assertEquals(16, native_count);
 // If no snapshot is used, only the 'gc' extension is loaded.
 // If snapshot is used, all extensions are cached in the snapshot.
 assertTrue(extension_count == 1 || extension_count == 5);