fix test-http-curl-chunk-problem.js and test-pipe-file-to-http.js on windows

test/common.js

@@ -54,12 +54,8 @@ exports.indirectInstanceOf = function(obj, cls) {
 
 exports.ddCommand = function(filename, kilobytes) {
   if (process.platform == 'win32') {
-    // 'fsutil file createnew' cannot be used on an existing file. If it
-    // already exists delete it.
-    if (require('path').existsSync(filename)) {
-      require('fs').unlinkSync(filename);
-    }
-    return 'fsutil.exe file createnew "' + filename + '" ' + (kilobytes * 1024);
+    return '"' + process.argv[0] + '" "' + path.resolve(exports.fixturesDir,
+      'create-file.js') + '" "' + filename + '" ' + (kilobytes * 1024);
   } else {
     return 'dd if=/dev/zero of="' + filename + '" bs=1024 count=' + kilobytes;
   }

test/fixtures/create-file.js

@@ -0,0 +1,29 @@
+// 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 fs = require('fs');
+
+var file_name = process.argv[2];
+var file_size = parseInt(process.argv[3]);
+
+var fd = fs.openSync(file_name, 'w');
+fs.truncateSync(fd, file_size);
+fs.closeSync(fd);