[clang] [CodeGen] [VTable] don't think linkonce vtable as unique (PR #197855)

[Jared Wyles via cfe-commits]

jaredwy wrote:

@ojhunt I think my position, after reading some of the newer additions to the spec along with the review that introduced this optimisation, is that it should not have either annotation. I do think local_unnamed_addr fits a little more tightly, and as you raised fixes the issue today. 

I think the spec is a little iffy around this whole area and does admit that its current approach may not be ideal (for rtti and there are ABI breaks) but I would argue it extends here as well. 

https://github.com/llvm/llvm-project/pull/197855