[llvm] [NFCI][Globals]For GlobalObjects, add updateSectionPrefix and change setSectionPrefix to handle empty strings (PR #158460)

[Teresa Johnson via llvm-commits]

https://github.com/teresajohnson commented:

The title and summary are both mechanical. Maybe add a 1 sentence description of why this change is needed?

https://github.com/llvm/llvm-project/pull/158460