`asyncio.create_subprocess_exec`: cannot read `/dev/stdin`

Dieses Issue hat noch niemand übernommen.

* **uvloop version**: `uvloop==0.17.0`
* **Python version**: `Python 3.10.10`
* **Platform**: `Linux 0af9a1603f81 5.10.76-linuxkit #1 SMP Mon Nov 8 10:21:19 UTC 2021 x86_64 GNU/Linux` (in a Docker container)
* **Can you reproduce the bug with `PYTHONASYNCIODEBUG` in env?**: yes
* **Does uvloop behave differently from vanilla asyncio? How?**: yes. Vanilla `asyncio` had a similar issue patched: https://github.com/python/cpython/issues/90522

Processes run with `asyncio.create_subprocess_exec` fail to read from `/dev/stdin` with `uvloop` but not with `asyncio`

`asyncio` had a similar issue fixed recently (in January 2022): https://github.com/python/cpython/issues/90522
This was backported to 3.10 and 3.11

I can reproduce this on Linux in a Docker container, with either Mac OS or Linux as hosts
I cannot reproduce this on Mac OS (seems to work fine)

Logs:
```
# PYTHONASYNCIODEBUG=1 python test.py
cat: /dev/stdin: No such device or address
Traceback (most recent call last):
File "//test.py", line 16, in
asyncio.run(f())
File "/usr/local/lib/python3.10/asyncio/runners.py", line 44, in run
return loop.run_until_complete(main)
File "uvloop/loop.pyx", line 1517, in uvloop.loop.Loop.run_until_complete
File "//test.py", line 13, in f
stdout, _ = await proc.communicate("test".encode("utf-8"))
File "/usr/local/lib/python3.10/asyncio/subprocess.py", line 195, in communicate
stdin, stdout, stderr = await tasks.gather(stdin, stdout, stderr)
File "/usr/local/lib/python3.10/asyncio/subprocess.py", line 147, in _feed_stdin
self.stdin.write(input)
File "/usr/local/lib/python3.10/asyncio/streams.py", line 325, in write
self._transport.write(data)
File "uvloop/handles/stream.pyx", line 674, in uvloop.loop.UVStream.write
File "uvloop/handles/handle.pyx", line 159, in uvloop.loop.UVHandle._ensure_alive
RuntimeError: unable to perform operation on ; the handler is closed
```

Expected (using `asyncio`):
```
# PYTHONASYNCIODEBUG=1 python test.py
b'test'
```

Code to reproduce:
```py
import asyncio

# Commenting out `uvloop` below fixes the issue
import uvloop
uvloop.install()

async def f():
proc = await asyncio.create_subprocess_exec(
"cat",
"/dev/stdin",
stdin=asyncio.subprocess.PIPE,
stdout=asyncio.subprocess.PIPE,
)
stdout, _ = await proc.communicate("test".encode("utf-8"))
print(stdout)

asyncio.run(f())
```

Beginne mit dem Reproducer in test.py und vergleiche sein Verhalten mit vanilla asyncio unter Linux in Docker. Verfolge die Behandlung von subprocess stdin durch uvloop/loop.pyx, uvloop/handles/stream.pyx und uvloop/handles/handle.pyx. Als abgeschlossen gilt die Aufgabe, wenn der `/dev/stdin`-Subprozess unter uvloop `b'test'` ausgibt, ohne dass der closed-transport error auftritt.

Vom Indexierungsmodell aus dem Issue-Text verfasst.