antithesis: Add shuffle-run.sh helper script

antithesis-tests/stress-composer/shuffle-run.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+# Get list of parallel*.py files into an array
+test_drivers=($(find . -name "parallel*.py"))
+
+# Exit if no files found
+[ ${#test_drivers[@]} -eq 0 ] && exit 1
+
+while true; do
+    # Pick a random file from the array
+    file=${test_drivers[$RANDOM % ${#test_drivers[@]}]}
+    python "$file" || exit $?
+done