Re-enable node fork specs

spec/node-spec.js

@@ -12,7 +12,7 @@ describe('node feature', () => {
 
   describe('child_process', () => {
     // TODO(alexeykuzmin): [Ch66] Time out. Fix them and enable.
-    xdescribe('child_process.fork', () => {
+    describe('child_process.fork', () => {
       it('works in current process', (done) => {
         const child = ChildProcess.fork(path.join(fixtures, 'module', 'ping.js'))
         child.on('message', (msg) => {