Using map instead of unordered_map to ensure reproducibility of k…

…ore definition generation (#1059)

We have seen that the `definition.kore` has been produced in a different
order depending on the OS, which creates a flaky error for some tools
like `llvm-komplie-compute-ordinal` and `llvm-kompile-compute-loc`, an
error on #1053 MacOS tests, and some frontend errors as well.

This PR aims to fix that issue by replacing the data structure used to
store the attributes.

include/kllvm/ast/attribute_set.h

@@ -1,10 +1,10 @@
 #ifndef KLLVM_ATTRIBUTES_H
 #define KLLVM_ATTRIBUTES_H
 
+#include <map>
 #include <memory>
 #include <optional>
 #include <string>
-#include <unordered_map>
 
 namespace kllvm {
 
@@ -29,8 +29,8 @@ class kore_composite_pattern;
  */
 class attribute_set {
 public:
-  using storage_t = std::unordered_map<
-      std::string, std::shared_ptr<kore_composite_pattern>>;
+  using storage_t
+      = std::map<std::string, std::shared_ptr<kore_composite_pattern>>;
 
   enum class key {
     Alias,