Fix calling trait methods from each other

An attempt to fix issue #4770 in the spirit of PR #5141.

Unfortunately (and a bit surprisingly), this fails when compiling stdlib:
```
  Compiling library std (/Users/anton/fuel/sway/sway-lib-std)

  Failed to compile std
  error
     --> /Users/anton/fuel/sway/sway-lib-std/src/hash.sw:322:41
      |
  320 |
  321 | #![inline(never)]
  322 | pub fn sha256<T>(s: T) -> b256 where T: Hash {
      |                                         ^^^^ Could not find symbol "Hash" in this scope.
  323 |     let mut hasher = Hasher::new();
  324 |     s.hash(hasher);
      |
  ____
```

sway-core/src/semantic_analysis/ast_node/declaration/impl_trait.rs

@@ -657,7 +657,7 @@ fn type_check_trait_implementation(
         }
     }
 
-    let mut all_items_refs: Vec<TyImplItem> = impld_item_refs.values().cloned().collect();
+    let all_items_refs_temp: Vec<TyImplItem> = impld_item_refs.values().cloned().collect();
 
     // Retrieve the methods defined on the trait declaration and transform
     // them into the correct typing for this impl block by using the type
@@ -684,6 +684,28 @@ fn type_check_trait_implementation(
         BTreeMap::new(),
         impld_item_refs,
     );
+
+    let mut all_items_refs: Vec<TyImplItem> = vec![];
+    for item in all_items_refs_temp.iter() {
+        match item {
+            TyImplItem::Fn(decl_ref) => {
+                let mut method = decl_engine.get_function(decl_ref);
+                method.replace_decls(&decl_mapping, handler, &mut ctx)?;
+                all_items_refs.push(TyImplItem::Fn(
+                    decl_engine
+                        .insert(method)
+                        .with_parent(decl_engine, (*decl_ref.id()).into()),
+                ));
+            }
+            TyImplItem::Constant(decl_ref) => {
+                let mut const_decl = decl_engine.get_constant(decl_ref);
+                const_decl.replace_decls(&decl_mapping, handler, &mut ctx)?;
+                all_items_refs.push(TyImplItem::Constant(decl_engine.insert(const_decl)));
+            }
+            TyImplItem::Type(_) => all_items_refs.push(item.clone()),
+        }
+    }
+
     for item in trait_items.iter() {
         match item {
             TyImplItem::Fn(decl_ref) => {