Don't cancel receive streams inside `.cancel_actor()`

We don't need to any more presuming you get ideal remote cancellation
conditions where the remote actor should teardown and kill the streams
from its end.

tractor/_portal.py

@@ -218,8 +218,6 @@ class Portal:
             log.cancel("This portal is already closed can't cancel")
             return False
 
-        await self._cancel_streams()
-
         log.cancel(
             f"Sending actor cancel request to {self.channel.uid} on "
             f"{self.channel}")

tractor/_spawn.py

@@ -203,7 +203,6 @@ async def soft_wait(
     # which will kill any waiting remote pdb trace).
     # This is a "soft" (cancellable) join/reap.
     try:
-        # await proc.wait()
         await wait_func(proc)
     except trio.Cancelled:
         # if cancelled during a soft wait, cancel the child