Add setImmediate() and clearImmediate() to the list of non-enumerable globals

[dchambers]

With the latest version of Sinon.JS (1.12.1) I see the following error when clock = sinon.useFakeTimers() is used within Mocha:

Error: global leaks detected: setImmediate, clearImmediate

even though I'm invoking clock.restore() within my afterEach() method. I raised this very same bug with Sinon.JS, but they said it was a Mocha issue, since:

They are restored, but the process of faking/restoring them copies them from window's prototype to window. This has been a known issue in the past: #143

Either apply the solution in #143 (comment) or ask the mocha team to add setImmediate and clearImmediate to the list of properties it should not detect as leaked globals.

They specifically pointed to this section of code within Mocha. Since this stuff should just work out of the box, I thought it was best to raise it here.

[boneskull]

after educating myself on setImmediate, seems OK

[dchambers]

👍