windows: correctly prep long path for fs.exists(Sync)

Closes GH-3739

lib/fs.js

@@ -87,14 +87,14 @@ fs.Stats.prototype.isSocket = function() {
 };
 
 fs.exists = function(path, callback) {
-  binding.stat(path, function(err, stats) {
+  binding.stat(pathModule._makeLong(path), function(err, stats) {
     if (callback) callback(err ? false : true);
   });
 };
 
 fs.existsSync = function(path) {
   try {
-    binding.stat(path);
+    binding.stat(pathModule._makeLong(path));
     return true;
   } catch (e) {
     return false;

test/simple/test-regress-GH-3739.js

@@ -0,0 +1,66 @@
+// 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.js'),
+    assert = require('assert'),
+    fs = require('fs'),
+    path = require('path');
+
+var dir = path.resolve(common.fixturesDir),
+    dirs = [];
+
+// Make a long path.
+for (var i = 0; i < 50; i++) {
+  dir = dir + '/123456790';
+  try {
+    fs.mkdirSync(dir, '0777');
+  } catch (e) {
+    if (e.code == 'EEXIST') {
+      // Ignore;
+    } else {
+      cleanup();
+      throw e;
+    }
+  }
+  dirs.push(dir);
+}
+
+// Test existsSync
+var r = fs.existsSync(dir);
+if (r !== true) {
+  cleanup();
+  throw new Error('fs.existsSync returned false');
+}
+
+// Text exists
+fs.exists(dir, function(r) {
+  cleanup();
+  if (r !== true) {
+    throw new Error('fs.exists reported false');
+  }
+});
+
+// Remove all created directories
+function cleanup() {
+  for (var i = dirs.length - 1; i >= 0; i--) {
+    fs.rmdirSync(dirs[i]);
+  }
+}