Add a comment and `TODO` about the action key determinism test.
Add a comment and `TODO` about the action key determinism test.

PiperOrigin-RevId: 409167032

katre/bazel,katre/bazel,katre/bazel,cushon/bazel,cushon/bazel,cushon/bazel,ButterflyNetwork/bazel,bazelbuild/bazel,ButterflyNetwork/bazel,ButterflyNetwork/bazel,katre/bazel,bazelbuild/bazel,cushon/bazel,bazelbuild/bazel,bazelbuild/bazel,katre/bazel,ButterflyNetwork/bazel,cushon/bazel,cushon/bazel,bazelbuild/bazel,ButterflyNetwork/bazel,katre/bazel,ButterflyNetwork/bazel,bazelbuild/bazel