few regressions tests fail under enable_openmp=0 with timeout

Some regressions tests fail under enable_openmp=0 with timeout
```bash
//tests/Examples/tfhe_rust:add_one_test TIMEOUT in 901.8s
/home/heiruser/.cache/bazel/_bazel_heiruser/a864f382268f12449bd3daa4685cd0c1/execroot/_main/bazel-out/k8-dbg/testlogs/tests/Examples/tfhe_rust/add_one_test/test.log
//tests/Examples/tfhe_rust:multi_output_test TIMEOUT in 900.0s
/home/heiruser/.cache/bazel/_bazel_heiruser/a864f382268f12449bd3daa4685cd0c1/execroot/_main/bazel-out/k8-dbg/testlogs/tests/Examples/tfhe_rust/multi_output_test/test.log
//tests/Examples/tfhe_rust_hl/cpu:add_round_key_test TIMEOUT in 900.1s
/home/heiruser/.cache/bazel/_bazel_heiruser/a864f382268f12449bd3daa4685cd0c1/execroot/_main/bazel-out/k8-dbg/testlogs/tests/Examples/tfhe_rust_hl/cpu/add_round_key_test/test.log
//tests/Examples/tfhe_rust_hl/cpu:arith_test TIMEOUT in 900.4s
/home/heiruser/.cache/bazel/_bazel_heiruser/a864f382268f12449bd3daa4685cd0c1/execroot/_main/bazel-out/k8-dbg/testlogs/tests/Examples/tfhe_rust_hl/cpu/arith_test/test.log
//tests/Examples/tfhe_rust_hl/cpu:fully_connected_test TIMEOUT in 901.1s
/home/heiruser/.cache/bazel/_bazel_heiruser/a864f382268f12449bd3daa4685cd0c1/execroot/_main/bazel-out/k8-dbg/testlogs/tests/Examples/tfhe_rust_hl/cpu/fully_connected_test/test.log
//tests/Examples/tfhe_rust_hl/cpu:hello_world_clean_xsmall_test TIMEOUT in 900.7s
/home/heiruser/.cache/bazel/_bazel_heiruser/a864f382268f12449bd3daa4685cd0c1/execroot/_main/bazel-out/k8-dbg/testlogs/tests/Examples/tfhe_rust_hl/cpu/hello_world_clean_xsmall_test/test.log

```

I suspect they need to be gated by enable_openmp=1 but of course no idea