[clang] [CodeGen] Revert "Generate assume loads only with -fstrict-vtable-pointers" (PR #91900)

[via cfe-commits]

AtariDreams wrote:

-fstrict-vtable-pointers IS experimental, but if you recall, this particular optimization was added to -fstrict-vtable-pointers because of the effects it had on compile-time, not because of correctness issues.

https://github.com/llvm/llvm-project/pull/91900