[clang] [Clang] Respect `-f[no]-offload-lto` universally in the driver (PR #184172)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

I'm also thinking a more correct approach is to have the offloading toolchains behave more normally but we default to `-foffload-lto=full` if unspecified. I think that change was actually quite annoying because we determine LTO elligibility before doing the offloading runtime detection.

https://github.com/llvm/llvm-project/pull/184172