[llvm] [NFCI][Globals] In GlobalObjects::setSectionPrefix, do conditional update if existing prefix is not equivalent to the new one. Returns whether prefix changed. (PR #158460)

[Mingming Liu via llvm-commits]

mingmingl-llvm wrote:

> These changes only started failing at head for me and on bots after this change. Are you able to take a look (and revert if investigation would take a while)?

done in https://github.com/llvm/llvm-project/pull/159159. Will investigate and try to re-land with a fix. Thanks for taking a look Aiden!

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