feat: support multiple valid hashes for each output file

tests/README.md

@@ -0,0 +1,17 @@
+Run the tests with
+
+```sh
+uv run run_tests.py
+```
+
+To update the hashes after a logic change, run the tests, then execute
+
+```sh
+cd TEST_DIR/model
+sha256sum * > ../SHA256SUMS.LABEL
+```
+
+where `LABEL` describes the type of system you are running the tests on.
+Since PyTorch does not guarantee exact cross-system reproducibility regardless of configuration,
+multiple valid hashes can be provided for each output file. The above update must be performed
+for each `TEST_DIR` and on each type of system.