Add initial tests for native ints.

Author: jnthn

t/nqp/64-native.t

@@ -0,0 +1,16 @@
+plan(4);
+
+{
+    my int $x;
+    ok(~$x eq '0', 'native int initialized to 0');
+    
+    $x := 42;
+    ok($x == 42, 'can set native int');
+    
+    sub foo() {
+        my $y := 58;
+        ok($x == 42, 'can access native ints from nested scopes');
+        ok($x + $y == 100, 'can add native ints to each other');
+    }
+    foo();
+}