fixes tproctypecache_falsepositive.nim test case

tests/generics/tproctypecache_falsepositive.nim

@@ -0,0 +1,17 @@
+
+import asyncdispatch
+
+type
+  Callback = proc() {.closure, gcsafe.}
+  GameState = ref object
+    playerChangeHandlers: seq[Callback]
+
+#proc dummy() =
+#  var x = newSeq[proc() {.cdecl, gcsafe.}]()
+
+proc newGameState(): GameState =
+  result = GameState(
+    playerChangeHandlers: newSeq[Callback]() # this fails
+  )
+
+#dummy()