(PUP-2738) Puppet::Util::Windows::Process FFI clean
- Refactor wait_process so that the FFI::MemoryPointer for the exit code is cleaned up immediately after use. Note that we capture the exit_status within the block, and return it outside of the block
- Fix bug in Puppet::Util::Windows::Process.process_privilege_symlink? that could result in the wrong value being returned.
- Fix bug in Puppet::Util::Windows::Process.elevated_security? that could result in the wrong value being returned.