[llvm] Update the EBO static_assert to dheck against APFloat::Storage instead of IEEEFloat. (PR #112589)

[Daniel Chen via llvm-commits]

DanielCChen wrote:

> > broke our downstream code as not all the members of APFloat is IEEE.
> 
> So I still see no reason to update the upstream code to handle this. Your downstream code is different and should change the assert there

Thanks for the comments. I totally understand your point.
In fact, we are in the process of upstreaming our downstream code as @Ariel-Burton stated in the "old" PR.
I think the question is if the change in this PR satisfies the purpose of the original assertion in PR #111641? If not, we can definitely look into it.

https://github.com/llvm/llvm-project/pull/112589