[3.15] gh-151540: Use a selector event loop in the happy-eyeballs tests (GH-153375) (#154623)

gh-151540: Use a selector event loop in the happy-eyeballs tests (GH-153375)
(cherry picked from commit a1ef41a)

Co-authored-by: Jakob Rossi <jmrossi98@gmail.com>

Author: miss-islington

Lib/test/test_asyncio/test_base_events.py

@@ -1092,7 +1092,11 @@ async def sock_connect(sock, address):
                 await asyncio.sleep(1)
             sock.connect(address)
 
-        loop = asyncio.new_event_loop()
+        # gh-151540: use a selector event loop instead of the platform
+        # default; the Windows proactor loop would register the mocked
+        # socket with a real IOCP handle instead of the mocked
+        # _add_reader/_add_writer below.
+        loop = asyncio.SelectorEventLoop()
         loop._add_writer = mock.Mock()
         loop._add_writer = mock.Mock()
         loop._add_reader = mock.Mock()
@@ -1124,7 +1128,8 @@ async def sock_connect(sock, address):
                 await asyncio.sleep(1)
             sock.connect(address)
 
-        loop = asyncio.new_event_loop()
+        # gh-151540: see test_create_connection_happy_eyeballs above.
+        loop = asyncio.SelectorEventLoop()
         loop._add_writer = mock.Mock()
         loop._add_writer = mock.Mock()
         loop._add_reader = mock.Mock()