lua: scoreboard iter — return; trailing-semi, collectgarbage/setfenv/getfenv/T stubs; all runnable tests reach execution

lib/lua/runtime.sx

@@ -1517,3 +1517,22 @@
 (dict-set! debug "getupvalue" (fn (&rest args) nil))
 (dict-set! debug "setupvalue" (fn (&rest args) nil))
 (dict-set! __package-loaded "debug" debug)
+
+;; collectgarbage stubs + env stubs
+(define
+  lua-collectgarbage
+  (fn (&rest args)
+    (cond
+      ((= (len args) 0) 0)
+      ((= (first args) "count") 0)
+      ((= (first args) "collect") 0)
+      (else 0))))
+
+(define collectgarbage lua-collectgarbage)
+
+;; setfenv/getfenv — Lua 5.1 env manipulation. Stubs.
+(define setfenv (fn (&rest args) (if (> (len args) 0) (first args) nil)))
+(define getfenv (fn (&rest args) _G))
+
+;; T — debug/testC placeholder for tests that check it conditionally
+(define T nil)