fix periodic snapshot upgrade edge cases

scripts/soak/run_soak.sh

@@ -497,7 +497,14 @@ import sys
 runs_root = pathlib.Path(sys.argv[1])
 delta_count = 0
 run_dirs = sorted(
-    [path for path in runs_root.glob("run_[0-9][0-9][0-9][0-9]") if path.is_dir()],
+    [
+        path
+        for path in runs_root.glob("run_*")
+        if path.is_dir()
+        and path.name.startswith("run_")
+        and path.name[4:].isdigit()
+    ],
+    key=lambda path: int(path.name[4:]),
     reverse=True,
 )
 for run_dir in run_dirs: