[lld] [lld][test] Fix file cleanup in aarch64-build-attributes.s (PR #164396)

[David Spickett via llvm-commits]

DavidSpickett wrote:

The inconsistency is the problem yes. That's the bit that will waste my time if I have to debug this test again.

Doing either is fine but tests should pick one or document why they need both. Not that I'm gonna hunt down the others but that's the principle.

https://github.com/llvm/llvm-project/pull/164396