[lld] [lld] Fix test failures when running as root user (PR #81339)

[Tom Stellard via llvm-commits]

tstellar wrote:

> Just curious, what were the failure messages?

All the tests that check file permissions fail when you run as root.  Here are some logs: https://github.com/tstellar/llvm-project/actions/runs/7830600066/job/21365140565

https://github.com/llvm/llvm-project/pull/81339