Detect lingering threads after tests (#37270)

* Detect lingering threads after tests

* Make sure cast is setup before checking state

* Make sure we ask executors of old hass to shutdown

We are not waiting here, just hoping for the best

* Make sure all instances of hass and executors is stopped.

Co-authored-by: Paulus Schoutsen <balloob@gmail.com>

* Also apply hass stopping to scripts

* Adjust to changes how we set up executor

* Add new CoreState.stopped

Co-authored-by: Paulus Schoutsen <balloob@gmail.com>

tests/components/cast/test_media_player.py

@@ -552,6 +552,7 @@ async def test_disconnect_on_stop(hass: HomeAssistantType):
 async def test_entry_setup_no_config(hass: HomeAssistantType):
     """Test setting up entry with no config.."""
     await async_setup_component(hass, "cast", {})
+    await hass.async_block_till_done()
 
     with patch(
         "homeassistant.components.cast.media_player._async_setup_platform",
@@ -567,6 +568,7 @@ async def test_entry_setup_single_config(hass: HomeAssistantType):
     await async_setup_component(
         hass, "cast", {"cast": {"media_player": {"host": "bla"}}}
     )
+    await hass.async_block_till_done()
 
     with patch(
         "homeassistant.components.cast.media_player._async_setup_platform",
@@ -582,6 +584,7 @@ async def test_entry_setup_list_config(hass: HomeAssistantType):
     await async_setup_component(
         hass, "cast", {"cast": {"media_player": [{"host": "bla"}, {"host": "blu"}]}}
     )
+    await hass.async_block_till_done()
 
     with patch(
         "homeassistant.components.cast.media_player._async_setup_platform",
@@ -598,6 +601,7 @@ async def test_entry_setup_platform_not_ready(hass: HomeAssistantType):
     await async_setup_component(
         hass, "cast", {"cast": {"media_player": {"host": "bla"}}}
     )
+    await hass.async_block_till_done()
 
     with patch(
         "homeassistant.components.cast.media_player._async_setup_platform",