Fix http_server_early_client_close_test.

A too early close of the HttpServer was responsible for an uncought
socket error. We now wait with HttpServer close to we

1) Have sent all data to the server.
2) The server are done receiving all data for the potential request.

BUG=http://code.google.com/p/dart/issues/detail?id=10408

Review URL: https://codereview.chromium.org//15719004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@23196 260f80e4-7a28-3924-810f-c04153c831b5
1 file changed