[llvm] [CodeGen] Use range-based for loops (NFC) (PR #138434)

[Nico Weber via llvm-commits]

nico wrote:

Also here: https://lab.llvm.org/buildbot/#/builders/24/builds/8041/steps/11/logs/stdio (first red build; has just this change).

https://github.com/llvm/llvm-project/pull/138434