message: Allow access to the module BufferLiveness applies to.
diff: @@ -67,6 +67,8 @@ class BufferLiveness {
  // Returns the underlying hlo ordering used for this liveness analysis.
  const HloOrdering& hlo_ordering() const { return *hlo_ordering_; }
  + const HloModule& module() const { return *module_; }
  +
  string ToString() const;
  static Colorer DefaultColorer() {
  