RFR: 8230203: Replace markWord enums with uintptr_t constants

[Doerr, Martin]

Hi Kim,

thanks for your explanations.

> What I think you want is
> C++11 explicitly typed enums, e.g. “enum : uintptr_t { … };”
Yes. That's what I meant.

> I agree there’s a lot less boilerplate with that.  But I like all the cast removals
> coming out of this change, and would rather not wait for those.
I also like the cast removals.

> There are still some issues with Solaris Studio.  Potential issues with other
> (more obscure) platforms.
I hope they can get resolved soon.

So wrt. to this issue, I abstain.
Cast removal looks good, tons of static consts look bad.

Best regards,
Martin