[clang] [CIR][OpenMP] Specify x86 host triple in target-parallel test (PR #234314)

[Erich Keane via cfe-commits]

erichkeane wrote:

Did a merge of this one to make sure buildbots for CIR are going green.  @jsjodin : Please feel free/let us know if there is anything you'd want to do differently with this, see the build failure here: https://lab.llvm.org/buildbot/#/builders/122/builds/246

https://github.com/llvm/llvm-project/pull/234314