asyncdispatch.nim recursion test. (#5534)

tests/async/tasyncrecursion.nim

@@ -0,0 +1,21 @@
+discard """
+  file: "tasyncrecursion.nim"
+  output: "50005000"
+"""
+import asyncdispatch
+
+proc asyncRecursionCycle*(counter: int): Future[int] =
+  var retFuture = newFuture[int]("asyncRecursionTest")
+  retFuture.complete(counter + 1)
+  return retFuture
+
+proc asyncRecursionTest*(): Future[int] {.async.} =
+  var i = 0
+  result = 0
+  while i < 10_000:
+    inc(result, await asyncRecursionCycle(i))
+    inc(i)
+
+when isMainModule:
+  var i = waitFor asyncRecursionTest()
+  echo i