flexiblas tests are consistently failing on ppc64le only.

With either openblas-0.3.26-4, LAPACK-xeigtsts_nep_in hangs, e.g. https://koji.fedoraproject.org/koji/taskinfo?taskID=113669862 and https://kojihub.stream.centos.org/koji/taskinfo?taskID=3637887

If that test is skipped, then a bunch of other tests fail: https://koji.fedoraproject.org/koji/taskinfo?taskID=113671107 and https://kojihub.stream.centos.org/koji/taskinfo?taskID=3639302

The same occurs with openblas-0.3.26-1 rebuilt with `%global build_type_safety_c 1`:

https://download.copr.fedorainfracloud.org/results/yselkowitz/openblas-bz2264712/fedora-40-ppc64le/07031762-flexiblas/builder-live.log
https://download.copr.fedorainfracloud.org/results/yselkowitz/openblas-bz2264712/fedora-40-ppc64le/07031785-flexiblas/builder-live.log

So it's not https://github.com/OpenMathLib/OpenBLAS/issues/4475 which was applied to get openblas building with gcc-14, and therefore possibly a GCC bug.

All other architectures are still building. Previous builds of flexiblas using openblas-0.3.26-1 (built with GCC 13 without those patches) built fine, even when flexiblas itself was built with GCC 14.

This is blocking the c10s bootstrap of flexiblas. Also, I wonder if this is related to the ppc64le test failures that we saw in scipy as well: https://gitlab.com/redhat/centos-stream/rpms/scipy/-/commit/1edeb822949e56c06940b3a17ea83481401c30e9

Also reported to Fedora which is also affected: https://bugzilla.redhat.com/show_bug.cgi?id=2264712