test(tvix/eval): Add proptests covering trait impls for String

Add a suite of proptests covering the laws of the handwritten stdlib
trait impls (Eq, Ord, and Hash) for String, generated from a new set of
macros for generating those tests which can be applied to other types.

Change-Id: Ib3276c9e96fca497aece094e5612707d3dc77ccd
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6626
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

tvix/eval/src/lib.rs

@@ -10,6 +10,8 @@ mod value;
 mod vm;
 mod warnings;
 
+#[cfg(test)]
+mod properties;
 #[cfg(test)]
 mod tests;