replace consume on hashmap/hashset with iterators

[thestinger]

These can just wrap the vector ones.

[bluss]

I'm looking at this. A tricky thing is that HashMap::consume empties the hashmap by mutable reference, while the consume iter takes it by value. Both alternatives have use cases.

This is problematic in librusti, which uses @mut HashMap and empties them with do map.consume ...

The workaround ends up looking like this:

@@ -163,7 +164,8 @@ impl Program {
             None => {}
         }

-        do self.newvars.consume |name, var| {
+        let newvars = util::replace(&mut self.newvars, HashMap::new());
+        for newvars.consume_iter().advance |(name, var)| {
             self.local_vars.insert(name, var);
         }

Not sure if this is acceptable.

[bluss]

is fixed

[huonw]

Fixed by #7833.