test: fix an expected result about RemoteTest#test_send

This PR fixed the following test.

```
Failure: test_send(RemoteTest)
/home/runner/work/rroonga/rroonga/tmp/test/test-remote.rb:97:in `test_send'
      94:     values = JSON.load(result)
      95:     values.delete("apache_arrow")
      96:     values.delete("features")
  =>  97:     assert_equal([
      98:                    "alloc_count",
      99:                    "cache_hit_rate",
     100:                    "command_version",
<["alloc_count",
 "cache_hit_rate",
 "command_version",
 "default_command_version",
 "max_command_version",
 "memory_map_size",
 "n_jobs",
 "n_queries",
 "start_time",
 "starttime",
 "uptime",
 "version"]> expected but was
<["alloc_count",
 "cache_hit_rate",
 "command_version",
 "default_command_version",
 "default_n_workers",
 "max_command_version",
 "memory_map_size",
 "n_jobs",
 "n_queries",
 "n_workers",
 "start_time",
 "starttime",
 "uptime",
 "version"]>

diff:
  ["alloc_count",
   "cache_hit_rate",
   "command_version",
   "default_command_version",
+  "default_n_workers",
   "max_command_version",
   "memory_map_size",
   "n_jobs",
   "n_queries",
+  "n_workers",
   "start_time",
   "starttime",
   "uptime",
   "version"]
```

test/test-remote.rb

@@ -98,11 +98,15 @@ def test_send
                    "alloc_count",
                    "cache_hit_rate",
                    "command_version",
+                   "cpu",
                    "default_command_version",
+                   "default_n_workers",
                    "max_command_version",
                    "memory_map_size",
                    "n_jobs",
                    "n_queries",
+                   "n_workers",
+                   "os",
                    "start_time",
                    "starttime",
                    "uptime",