module: use path.sep instead of custom solution

Instead of using a custom solution for path delimiters we can use
path.sep in Module._initPaths

lib/module.js

@@ -516,8 +516,7 @@ Module._initPaths = function() {
   }
 
   if (process.env['NODE_PATH']) {
-    var splitter = isWindows ? ';' : ':';
+    paths = process.env['NODE_PATH'].split(path.delimiter).concat(paths);
-    paths = process.env['NODE_PATH'].split(splitter).concat(paths);
   }
 
   modulePaths = paths;

test/simple/test-module-globalpaths-nodepath.js

@@ -0,0 +1,46 @@
+// 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 module = require('module');
+
+var isWindows = process.platform === 'win32';
+
+var partA, partB;
+
+if (isWindows) {
+  partA = 'C:\\Users\\Rocko Artischocko\\AppData\\Roaming\\npm';
+  partB = 'C:\\Program Files (x86)\\nodejs\\';
+  process.env['NODE_PATH'] = partA + ';' + partB;
+} else {
+  partA = '/usr/test/lib/node_modules';
+  partB = '/usr/test/lib/node';
+  process.env['NODE_PATH'] = partA + ':' + partB;
+}
+
+module._initPaths();
+
+assert.ok(module.globalPaths.indexOf(partA) !== -1);
+assert.ok(module.globalPaths.indexOf(partB) !== -1);
+
+assert.ok(Array.isArray(module.globalPaths));