[llvm] [SHT_LLVM_BB_ADDR_MAP] Avoids side-effects in addition since order is unspecified. (PR #79168)

[James Henderson via llvm-commits]

https://github.com/jh7370 approved this pull request.

Nice find! LGTM, but please give it a bit before landing.

https://github.com/llvm/llvm-project/pull/79168