fix dump() recursion detection

only detect recursions for table values.

frontend/dump.lua

@@ -13,6 +13,7 @@ local function _serialize(what, outt, indent, max_lv, history)
         return
     end
 
+    if type(what) == "table" then
         history = history or {}
         for up, item in ipairs(history) do
             if item == what then
@@ -22,8 +23,6 @@ local function _serialize(what, outt, indent, max_lv, history)
                 return
             end
         end
-
-    if type(what) == "table" then
         local new_history = { what, unpack(history) }
         local didrun = false
         insert(outt, "{")