test: address timing issues in simple http tests

simple tests test-http-request-end.js, test-http-default-encoding.js
hangs in AIX. The root cause for both the failures is related to the
timing with which packets are sent between the client and server.
On the client side, one factor that affects the timing is Nagle's
algorithm. With Nagle enabled there may be a delay between two packets
as the stack may wait until either:
  a. An acknowledgement for the first packet is received, or
  b. 200 ms elapses.
before sending the second packet.

Similarly at the server side 2 sequential packages can be delivered to
the application either together or separatly.

On AIX we see that they are delivered separately to the server, while on
Linux delivered together. If we change the timing, for example disabling
Nagle on AIX we see the 2 packets delivered together and the tests pass.

In the test case simple/test-http-request-end.js, the client request
handler of the server receives and stores the data in a data callback,
closes the server in a request end callback, and writes to the client
and ends the response, in-line with the request receipt. An HTTP parser
module parses the incoming message, and invokes callback routines which
are registered for HTTP events (such as header, body, end etc.)

Because the termination sequence arrive in a separate packet, there is a
delay in parsing that message and identify that the client request ended
(and thereby invoke the request end call backhandler). Due to this delay,
the response close happens first, which in-turn destroys the server
socket leading to the fd and watcher removal from the uv loop abandoning
further events on this connection, and end call back never being called,
causing the reported hang.  simple/test-http-default-encoding.js suffers
from the same problem.

Also, remove the timer logic from the test case. Test harness anyways
contain a timer which controls the individual tests so remove such
controls from the test case, as suggested by @tjfontaine

Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
PR-URL: https://github.com/joyent/node/pull/9432

PORT-FROM: joyent/node @ 13e1131406
PR-URL: https://github.com/nodejs/io.js/pull/2294
Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

test/parallel/test-http-default-encoding.js

@@ -11,16 +11,11 @@ var server = http.Server(function(req, res) {
   req.on('data', function(chunk) {
     result += chunk;
   }).on('end', function() {
-    clearTimeout(timeout);
     server.close();
+    res.writeHead(200);
+    res.end('hello world\n');
   });
 
-  var timeout = setTimeout(function() {
-    process.exit(1);
-  }, 100);
-
-  res.writeHead(200);
-  res.end('hello world\n');
 });
 
 server.listen(common.PORT, function() {

test/parallel/test-http-request-end.js

@@ -14,10 +14,10 @@ var server = http.Server(function(req, res) {
 
   req.on('end', function() {
     server.close();
+    res.writeHead(200);
+    res.end('hello world\n');
   });
 
-  res.writeHead(200);
-  res.end('hello world\n');
 });
 
 server.listen(common.PORT, function() {