fs: fix functions executed in wrong context

The callback should run in the global scope and not in the FSReqWrap
context.

Author: BridgeAR

lib/fs.js

@@ -737,7 +737,7 @@ fs.ftruncateSync = function(fd, len = 0) {
 };
 
 fs.rmdir = function(path, callback) {
-  callback = maybeCallback(callback);
+  callback = makeCallback(callback);
   path = getPathFromURL(path);
   validatePath(path);
   const req = new FSReqWrap();
@@ -1784,7 +1784,7 @@ fs.realpath = function realpath(p, options, callback) {
 
 
 fs.realpath.native = function(path, options, callback) {
-  callback = maybeCallback(callback || options);
+  callback = makeCallback(callback || options);
   options = getOptions(options, {});
   path = getPathFromURL(path);
   validatePath(path);

test/parallel/test-fs-mkdir-rmdir.js

@@ -29,6 +29,7 @@ fs.mkdir(d, 0o666, common.mustCall(function(err) {
   assert.ifError(err);
 
   fs.mkdir(d, 0o666, common.mustCall(function(err) {
+    assert.strictEqual(this, undefined);
     assert.ok(err, 'got no error');
     assert.ok(/^EEXIST/.test(err.message), 'got no EEXIST message');
     assert.strictEqual(err.code, 'EEXIST', 'got no EEXIST code');

test/parallel/test-fs-realpath-native.js

@@ -6,7 +6,8 @@ const fs = require('fs');
 if (!common.isOSX) common.skip('MacOS-only test.');
 
 assert.strictEqual(fs.realpathSync.native('/users'), '/Users');
-fs.realpath.native('/users', common.mustCall((err, res) => {
+fs.realpath.native('/users', common.mustCall(function(err, res) {
   assert.ifError(err);
   assert.strictEqual(res, '/Users');
+  assert.strictEqual(this, undefined);
 }));