Revert "[OpenMP] Disable flaky barrier fence test (#85093)"

This reverts commit cd8843f87af2f04a85dda12b37738596cbf4cd5e.

Originally disabled to try to unstick the AMD build bot, didn't make a
difference after a week so it goes back in.

GitOrigin-RevId: 5cccc405e3981dfb97d5fee05b44a2ac6388191c
diff --git a/libomptarget/test/offloading/barrier_fence.c b/libomptarget/test/offloading/barrier_fence.c
index 9c3027f..b9a8ca2 100644
--- a/libomptarget/test/offloading/barrier_fence.c
+++ b/libomptarget/test/offloading/barrier_fence.c
@@ -3,10 +3,6 @@
 // RUN: %libomptarget-compileopt-generic -fopenmp-offload-mandatory -O3
 // RUN: %libomptarget-run-generic
 
-// FIXME: This test is flaky on all targets
-// UNSUPPORTED: amdgcn-amd-amdhsa
-// UNSUPPORTED: nvptx64-nvidia-cuda
-// UNSUPPORTED: nvptx64-nvidia-cuda-LTO
 // UNSUPPORTED: aarch64-unknown-linux-gnu
 // UNSUPPORTED: aarch64-unknown-linux-gnu-LTO
 // UNSUPPORTED: x86_64-pc-linux-gnu