Test with nodeunit 0.5.3 hangs used to work with 0.5.1

Following test hangs with 0.5.3 but works with 0.5.1

``` javascript
var net = require('net');

exports['init-conn-test'] = function (test) {
var someServer = net.createServer();
var port = 1122;

var done = false;

var interval = setInterval(function() {
if (!done) {
test.ok(false, 'init-conn-test is expected to finish in 3 secs');
test.done();
}
try {
someServer.close();
}
catch(e) {
// eat it
}
clearInterval(interval);
}, 3000);

someServer.on('connection', function(sock) {
sock.on('data', function(data) {
lastEvent = data;
test.deepEqual(data.toString(), 'Testing123');
try {
someServer.close();
}
catch(e) {
// eat it
}
done = true;
clearInterval(interval);
test.done();
})
});

someServer.listen(port, 'localhost', function() {
var socket = net.createConnection(port, 'localhost');
socket.write('Testing123');
});
};
```

Start by running the supplied test with nodeunit 0.5.3 and 0.5.1 to reproduce the hang and compare behavior. Trace the test runner's handling of the asynchronous net server, socket, interval, and test.done calls. Done means the test completes within the expected time on 0.5.3 without changing the test's intended assertions.

Written by the indexing model from the issue text.