CM-1587 (Mark/Cory) Win32 helpers to support fast automation tests

@markbenvenuto @corymintz Some more Win32 helpers to support the fast automation tests.
It doesn't.  An error means that there was an error, which is why we're returning `false, err` rather than `false, nil`.  A return value of `WAIT_OBJECT_0` means that the zero-timeout wait succeeded, meaning that the process is a zombie.