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

[Arthur Eubanks via cfe-commits]

aeubanks 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.

can you clarify what you mean by "this particular optimization"? you mean adding or not adding assume loads?

when I said "regress", I meant runtime performance, not compile times, I should have been clearer

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