Tests: adapted js_internal_redirect.t to njs changes.

req.variables.arg_dest can be undefined if dest argument
is not present.

js_internal_redirect.t

diff --git a/js_internal_redirect.t b/js_internal_redirect.t
index 16633bd..a5c5bd6 100644
--- a/js_internal_redirect.t
+++ b/js_internal_redirect.t
@@ -68,7 +68,7 @@
     }
 
     function test_redirect(req) {
-        if (req.variables.arg_dest.startsWith('named')) {
+        if (req.variables.arg_dest == 'named') {
             req.internalRedirect('\@named');
 
         } else {