When inspector url has autoclose=true, then upon detach, frontend closes...

... instead of trying to reconnect.

Also, node-debug sets autoclose=true on the url.

addresses #472 
I prefer to see here:
```
var query = {
  port: debugPort,
  autoclose: autoclose === true
};
```
or
```
var query = {
  port: debugPort
};
if (autoclose) query.autoclose = true;
```
The second way more verbose, but avoids modification of tests