[test] Add core `test-http-client-upload-buf` test

Modifications:

  * make client connect to `PROXY_PORT` instead of `PORT`

test/core/simple/test-http-client-upload-buf.js

+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var common = require('../common');
+var assert = require('assert');
+var http = require('http');
+
+var N = 1024;
+var bytesRecieved = 0;
+var server_req_complete = false;
+var client_res_complete = false;
+
+var server = http.createServer(function(req, res) {
+  assert.equal('POST', req.method);
+
+  req.on('data', function(chunk) {
+    bytesRecieved += chunk.length;
+  });
+
+  req.on('end', function() {
+    server_req_complete = true;
+    console.log('request complete from server');
+    res.writeHead(200, {'Content-Type': 'text/plain'});
+    res.write('hello\n');
+    res.end();
+  });
+});
+server.listen(common.PORT);
+
+server.on('listening', function() {
+  var req = http.request({
+    port: common.PROXY_PORT,
+    method: 'POST',
+    path: '/'
+  }, function(res) {
+    res.setEncoding('utf8');
+    res.on('data', function(chunk) {
+      console.log(chunk);
+    });
+    res.on('end', function() {
+      client_res_complete = true;
+      server.close();
+    });
+  });
+
+  req.write(new Buffer(N));
+  req.end();
+
+  common.error('client finished sending request');
+});
+
+process.on('exit', function() {
+  assert.equal(N, bytesRecieved);
+  assert.equal(true, server_req_complete);
+  assert.equal(true, client_res_complete);
+});