[3.14] gh-136447: Use `self.loop` instead of global `loop` variable in asyncio REPL (GH-136448) (#136458)

gh-136447: Use `self.loop` instead of global `loop` variable in asyncio REPL (GH-136448)
(cherry picked from commit 77fa7a4dcc771bf4d297ebfd4f357483d0750a1c)

Co-authored-by: Justin Su <injustsu@gmail.com>