fix test-child-process-env on windows

test/simple/test-child-process-env.js

@@ -24,6 +24,8 @@ var assert = require('assert');
 
 var spawn = require('child_process').spawn;
 
+var isWindows = process.platform === 'win32';
+
 var env = {
   'HELLO': 'WORLD'
 };
@@ -31,7 +33,12 @@ env.__proto__ = {
   'FOO': 'BAR'
 }
 
-var child = spawn('/usr/bin/env', [], {env: env});
+if (isWindows) {
+  var child = spawn('cmd.exe', ['/c set'], {env: env});
+} else {
+  var child = spawn('/usr/bin/env', [], {env: env});
+}
+
 
 var response = '';