Add support for Sega Mega-CD 32X / Sega CD 32X (6 titles)

[ghost]

So far, bizhawk emulate perfectly all of my retro games except a few rare Sega CD 32X games, it would be nice if the emulator can support them.

[Spikestuff]

MegaCD/SegaCD: #1406

As for 32X well that's already supported.
Just some games have issues: #927

Here's DOOM 32X working for example:

[Sappharad]

@Spikestuff I don't think you understand this user's request.

There are but six games that require BOTH the 32x and MegaCD at the same time. As far as I know, we can't do that right now because BizHawk uses different cores for 32x and MegaCD.

https://segaretro.org/Sega_Mega-CD_32X

edit: it's six --yoshi

[Spikestuff]

@Sappharad I wrote my comment that way due to how the title is written as "Sega CD/32X" instead of having of using a space like it does in the comments and the part of written the comments also off'd me.

@YoshiRulz Suggestion to attempt to make it work in the PicoDrive core instead of the Gens core as Pico already has the 32x support.

[YoshiRulz]

Not sure if adding this to PicoDrive is the right way to do it, but it'll probably be easier so relabeled.

[ghost]

So far, only Fusion is able to support the 6 CD 32X games (I have never personally tested Surgical Strike though) . If I remember, that emulator is closed source right?

[nattthebear]

@Glitcholog I believe you're correct, since I tried one of these games in our picodrive core once, which, despite having mega CD and 32X attachments, didn't work with both of them enabled at once. (#927 (comment)) But is that documented somewhere? Do we know what's going on that 32X and CD needs that 32X or CD emulators don't do?