[llvm] [Dexter] Extend XFAIL of Dexter tests to all MacOS architectures. (PR #83936)

[via llvm-commits]

dyung wrote:

@adrian-prantl I noticed that you removed the XFAIL for all of darwin in 536e0ebaaa842471ae91bbda4f8cc1821690861e, and then the test started to fail on one of my bots https://lab.llvm.org/buildbot/#/builders/280/builds/68, and I am guessing it will be failing on my other bot (https://lab.llvm.org/staging/#/builders/188) once it gets to your commit.

Are the bots I setup misconfigured in some manner? These tests have always been failing for me on the x86 bot at least (see https://lab.llvm.org/staging/#/builders/188/builds/400 for example), and it never failed previously on the AArch64 bot because it was previously XFAIL'd there as well.

https://github.com/llvm/llvm-project/pull/83936