Revert "bpo-34037, asyncio: add BaseEventLoop.wait_executor_on_close (GH-13786)" (#13802)

This reverts commit 0f0a30f4da4b529e0f7df857b9f575b231b32758.
diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst
index f75ca9a..8673f84 100644
--- a/Doc/library/asyncio-eventloop.rst
+++ b/Doc/library/asyncio-eventloop.rst
@@ -140,18 +140,12 @@
    The loop must not be running when this function is called.
    Any pending callbacks will be discarded.
 
-   This method clears all queues and shuts down the default executor. By
-   default, it waits for the default executor to finish. Set
-   *loop.wait_executor_on_close* to ``False`` to not wait for the executor.
+   This method clears all queues and shuts down the executor, but does
+   not wait for the executor to finish.
 
    This method is idempotent and irreversible.  No other methods
    should be called after the event loop is closed.
 
-   .. versionchanged:: 3.8
-      The method now waits for the default executor to finish by default.
-      Added *loop.wait_executor_on_close* attribute.
-
-
 .. coroutinemethod:: loop.shutdown_asyncgens()
 
    Schedule all currently open :term:`asynchronous generator` objects to