[llvm] Warn on align directive with non-zero fill value in virtual sections (PR #66792)

[Luís Marques via llvm-commits]

luismarques wrote:

@MatzeB You're right, this patch was flawed. My original patch also checked the non-zero fill value but, for whatever reason, I seem to have removed that before I submitted the PR. Apologies. Here's a fix: #67237. @s-barannikov 

https://github.com/llvm/llvm-project/pull/66792