testing: migrate compute-levels.sh

this test wasn't even run

Change-Id: I735c8b2d2c63a65c665d6344a98ddb3bbbf94f43

tests/functional/compute-levels.sh

@@ -1,7 +0,0 @@
-source common.sh
-
-if [[ $(uname -ms) = "Linux x86_64" ]]; then
-    # x86_64 CPUs must always support the baseline
-    # microarchitecture level.
-    nix -vv --version | grepQuiet "x86_64-v1-linux"
-fi

tests/functional2/cli/test_compute_levels.py

@@ -0,0 +1,11 @@
+import os
+import sys
+import pytest
+from testlib.fixtures.nix import Nix
+
+
+@pytest.mark.skipif(
+    sys.platform != "linux" or os.uname().machine != "x86_64", reason="uarch levels are x86_64 only"
+)
+def test_compute_levels(nix: Nix):
+    assert "x86_64-v1-linux" in nix.nix(["-vv", "--version"]).run().ok().stdout_plain