Removed oldIterTranf feature

tests/async/tasynctry2.nim

@@ -1,18 +0,0 @@
-discard """
-  file: "tasynctry2.nim"
-  errormsg: "\'yield\' cannot be used within \'try\' in a non-inlined iterator"
-  line: 14
-"""
-import asyncdispatch
-
-{.experimental: "oldIterTransf".}
-
-proc foo(): Future[bool] {.async.} = discard
-
-proc test5(): Future[int] {.async.} =
-  try:
-    discard await foo()
-    raise newException(ValueError, "Test5")
-  except:
-    discard await foo()
-    result = 0