stage2 大量优化代码使其自举编译时间大幅缩短

stage2/attr.spl

@@ -132,11 +132,7 @@ fn drop(self: *Attr) {
 
 fn node(self: *Attr, id: usize): *AttrNode {
     if id == 0 || id >= self.table.len { ret null; }
-    match Vec.get(&self.table, id) {
-        .Ok(ptr) => { ret ptr as *AttrNode; },
-        .Err(error) => { ret null; },
-    }
-    ret null;
+    ret (self.table.data as *AttrNode) + id;
 }
 
 fn info_at(self: *Attr, index: usize): *AttrInfo {