[llvm] [XCOFF] make related SD symbols as isFunction (PR #69553)

[James Henderson via llvm-commits]

https://github.com/jh7370 commented:

@chenzheng1030, as per https://discourse.llvm.org/t/rfc-github-pr-resolve-conversation-button/73178, please don't click the "resolve conversation" button after replying to a reviewer comment, especially if you don't agree with their suggestion, as it hides the conversation from view and makes it a pain to find it so that the reviewer can follow up as I have done here.

https://github.com/llvm/llvm-project/pull/69553