[llvm] [BOLT] Add CustomOffset flag for optimizing kernel (PR #98153)

[via llvm-commits]

lifengxiang1025 wrote:

> I still don't understand the rationale for this change. Can you explain why they're not in sync? Also, we need a testcase.

After deactivating KASLR(https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/7/html/virtualization_security_guide/sect-virtualization_security_guide-guest_security-kaslr#sect-virtualization_security_guide-guest_security-KASLR), I found the offset disappear. I'll add a testcase soon. 

https://github.com/llvm/llvm-project/pull/98153