[llvm] [NFC][OpenMP] Update a test that was failing on aarch64. (PR #164456)

[Michał Górny via llvm-commits]

mgorny wrote:

With this patch on top of e0bc38226c903937faaef9766b76bda9e8f0cb5d, I'm seeing:

```
# .---redirected output from '/var/tmp/portage/llvm-runtimes/offload-22.0.0.9999/work/runtimes_build/offload/test/aarch64-unknown-linux-gnu/offloading/Output/bug51781.c.tmp.custom'
# | /usr/bin/aarch64-unknown-linux-gnu-ld: unrecognised emulation mode: llvm=-openmp-opt-disable-spmdization
# | Supported emulations: aarch64linux aarch64elf aarch64elf32 aarch64elf32b aarch64elfb armelf armelfb aarch64linuxb aarch64linux32 aarch64linux32b armelfb_linux_eabi armelf_linux_eabi
# | clang: error: linker command failed with exit code 1 (use -v to see invocation)
# | /usr/lib/llvm/22/bin/clang-linker-wrapper: error: 'clang' failed
# | aarch64-unknown-linux-gnu-clang: error: linker command failed with exit code 1 (use -v to see invocation)
# `-----------------------------
```

Do I need to rebuild with latest `main`?

https://github.com/llvm/llvm-project/pull/164456