Router: fixed "not empty" pattern matching.

The "!" pattern should be opposite to "", i.e. match only non-empty values.
But after 3c00af54b937 it was equal to "!*", which is wrong.

src/nxt_http_route.c

@@ -1085,10 +1085,6 @@ nxt_http_route_pattern_create(nxt_task_t *task, nxt_mp_t *mp,
 
         pattern->negative = 1;
         pattern->any = 0;
-
-        if (test.length == 0) {
-            return NXT_OK;
-        }
     }
 
     if (test.length == 0) {

test/test_routing.py

@@ -118,6 +118,9 @@ class TestRouting(TestApplicationProto):
 
     def test_routes_match_negative(self):
         self.route_match({"uri": "!"})
+        assert self.get()['status'] == 200
+
+        self.route_match({"uri": "!*"})
         assert self.get()['status'] == 404
 
         self.route_match({"uri": "!/"})
@@ -1187,6 +1190,18 @@ class TestRouting(TestApplicationProto):
         assert self.get(url='/?foo=barxx&x%=%')['status'] == 404
 
     def test_routes_match_arguments_negative(self):
+        self.route_match({"arguments": {"foo": "!"}})
+        assert self.get(url='/?bar')['status'] == 404
+        assert self.get(url='/?foo')['status'] == 404
+        assert self.get(url='/?foo=')['status'] == 404
+        assert self.get(url='/?foo=%25')['status'] == 200
+
+        self.route_match({"arguments": {"foo": "!*"}})
+        assert self.get(url='/?bar')['status'] == 404
+        assert self.get(url='/?foo')['status'] == 404
+        assert self.get(url='/?foo=')['status'] == 404
+        assert self.get(url='/?foo=blah')['status'] == 404
+
         self.route_match({"arguments": {"foo": "!%25"}})
         assert self.get(url='/?foo=blah')['status'] == 200
         assert self.get(url='/?foo=%')['status'] == 404