test: remove the use of curl in the test suite

There were 2 tests using curl:

`test-http-304.js` is removed because it was initially included to test
that the 304 response does not contain a body, and this is already
covered by `test-http-chunked-304.js`.

`test-http-curl-chunk-problem` has been renamed and refactored so
instead of using curl, it uses 2 child node processes: one for sending
the HTTP request and the other to calculate the sha1sum. Originally,
this test was introduced to fix a bug in `nodejs@0.2.x`, and it was not
fixed until `nodejs@0.2.5`. A modified version of this test has been run
with `nodejs@0.2.0` and reproduces the problem. This same test has been
run with `nodejs@0.2.6` and runs correctly.

Fixes: #5174
PR-URL: #5750
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

Author: santigimeno

test/parallel/test-http-304.js

@@ -0,0 +1,93 @@
+'use strict';
+// http://groups.google.com/group/nodejs/browse_thread/thread/f66cd3c960406919
+const common = require('../common');
+const assert = require('assert');
+if (!common.hasCrypto) {
+  console.log('1..0 # Skipped: missing crypto');
+  return;
+}
+
+if (process.argv[2] === 'request') {
+  const http = require('http');
+  const options = {
+    port: common.PORT,
+    path : '/'
+  };
+
+  http.get(options, (res) => {
+    res.pipe(process.stdout);
+  });
+
+  return;
+}
+
+if (process.argv[2] === 'shasum') {
+  const crypto = require('crypto');
+  const shasum = crypto.createHash('sha1');
+  process.stdin.on('data', (d) => {
+    shasum.update(d);
+  });
+
+  process.stdin.on('close', () => {
+    process.stdout.write(shasum.digest('hex'));
+  });
+
+  return;
+}
+
+const http = require('http');
+const cp = require('child_process');
+
+const filename = require('path').join(common.tmpDir, 'big');
+
+function executeRequest(cb) {
+  cp.exec([process.execPath,
+           __filename,
+           'request',
+           '|',
+           process.execPath,
+           __filename,
+           'shasum' ].join(' '),
+          (err, stdout, stderr) => {
+            if (err) throw err;
+            assert.equal('8c206a1a87599f532ce68675536f0b1546900d7a',
+                         stdout.slice(0, 40));
+            cb();
+          }
+  );
+}
+
+
+common.refreshTmpDir();
+
+const ddcmd = common.ddCommand(filename, 10240);
+
+cp.exec(ddcmd, function(err, stdout, stderr) {
+  if (err) throw err;
+  const server = http.createServer(function(req, res) {
+    res.writeHead(200);
+
+    // Create the subprocess
+    const cat = cp.spawn('cat', [filename]);
+
+    // Stream the data through to the response as binary chunks
+    cat.stdout.on('data', (data) => {
+      res.write(data);
+    });
+
+    cat.stdout.on('end', () => res.end());
+
+    // End the response on exit (and log errors)
+    cat.on('exit', (code) => {
+      if (code !== 0) {
+        console.error('subprocess exited with code ' + code);
+        process.exit(1);
+      }
+    });
+
+  });
+
+  server.listen(common.PORT, () => {
+    executeRequest(() => server.close());
+  });
+});