tests/run-tests: disable nightly.TestCase on non-Linux until its ported

tests/run-tests

@@ -174,6 +174,10 @@ for testcase in $WORKSPACE/tests/*.TestCase; do
         echo "skipping install.TestCase, its too troublesome in CI builds"
         continue
     fi
+    if [ $(uname) != "Linux" ] && [ $testcase == $WORKSPACE/tests/nightly.TestCase ]; then
+        echo "skipping nightly.TestCase, it currently only works GNU/Linux"
+        continue
+    fi
     $testcase
 done