[opengl32] Add stub for wglSwapMultipleBuffers

[Marvin]

Hi,

While running your changed tests, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?

Full results can be found at:
https://testbot.winehq.org/JobDetails.pl?Key=70765

Your paranoid android.


=== debiant (build log) ===

Task: make_opengl failed

=== debiant (build log) ===

Task: make_opengl failed