test: update cwd-enoent tests for AIX

On AIX you can not remove a directory that you are currently inside of
as it results in an EBUSY error. "EBUSY: resource busy or locked".
Updated the tests accordingly so that they are skipped on AIX.

PR-URL: https://github.com/nodejs/node/pull/2909
Reviewed-By: Ben Noordhuis <ben@strongloop.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

test/parallel/test-cwd-enoent-preload.js

@@ -4,8 +4,8 @@ const assert = require('assert');
 const fs = require('fs');
 const spawn = require('child_process').spawn;
 
-// Fails with EINVAL on SmartOS, EBUSY on Windows.
+// Fails with EINVAL on SmartOS, EBUSY on Windows, EBUSY on AIX.
-if (process.platform === 'sunos' || common.isWindows) {
+if (process.platform === 'sunos' || common.isWindows || common.isAix) {
   console.log('1..0 # Skipped: cannot rmdir current working directory');
   return;
 }

test/parallel/test-cwd-enoent-repl.js

@@ -4,8 +4,8 @@ var assert = require('assert');
 var fs = require('fs');
 var spawn = require('child_process').spawn;
 
-// Fails with EINVAL on SmartOS, EBUSY on Windows.
+// Fails with EINVAL on SmartOS, EBUSY on Windows, EBUSY on AIX.
-if (process.platform === 'sunos' || common.isWindows) {
+if (process.platform === 'sunos' || common.isWindows || common.isAix) {
   console.log('1..0 # Skipped: cannot rmdir current working directory');
   return;
 }

test/parallel/test-cwd-enoent.js

@@ -4,8 +4,8 @@ var assert = require('assert');
 var fs = require('fs');
 var spawn = require('child_process').spawn;
 
-// Fails with EINVAL on SmartOS, EBUSY on Windows.
+// Fails with EINVAL on SmartOS, EBUSY on Windows, EBUSY on AIX.
-if (process.platform === 'sunos' || common.isWindows) {
+if (process.platform === 'sunos' || common.isWindows || common.isAix) {
   console.log('1..0 # Skipped: cannot rmdir current working directory');
   return;
 }