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

[Matt Arsenault via llvm-commits]

arsenm 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 


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