Fix enif_select 'stealing control' warning in asyncio tests

Add 50ms delay in end_per_testcase to allow async FD cleanup
(enif_select STOP events) to complete before the next test starts.
This prevents race conditions when the OS reuses FD numbers.

Author: benoitc

test/py_asyncio_compat_SUITE.erl

@@ -130,6 +130,10 @@ init_per_testcase(_TestCase, Config) ->
     Config.
 
 end_per_testcase(_TestCase, _Config) ->
+    %% Allow time for async FD cleanup (enif_select STOP events)
+    %% to complete before the next test starts. This prevents
+    %% "stealing control" warnings when FDs are reused.
+    timer:sleep(50),
     ok.
 
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