test(tvix/eval): Add proof-of-concept test for Chunk

This is pretty boring at the moment, but mostly serves as a foot in the
door in the direction of writing more tests

Change-Id: Id88eb4ec7e53ebb2d5b5c254c8f45ff750238811
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6637
Autosubmit: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

tvix/eval/src/lib.rs

@@ -13,6 +13,8 @@ mod warnings;
 #[cfg(test)]
 mod properties;
 #[cfg(test)]
+mod test_utils;
+#[cfg(test)]
 mod tests;
 
 // Re-export the public interface used by other crates.