Flaky dataflow sanitizer test

Hi all,

One of the dfsan tests seems to be failing non-deterministically on AArch64:
http://lab.llvm.org:8011/builders/clang-cmake-aarch64-full/builds/3021
http://lab.llvm.org:8011/builders/clang-cmake-aarch64-full/builds/2966
http://lab.llvm.org:8011/builders/clang-cmake-aarch64-full/builds/2838
http://lab.llvm.org:8011/builders/clang-cmake-aarch64-full/builds/2812

Any idea what those segfaults are about? Has anyone seen them on other
platforms?

Thanks,
Diana