Task should be `executing` upon rejoining.

**What happened**:

When a task secedes from the threadpool, it takes the state `long-running` when rejoining, the state stays `long-running`.

**What you expected to happen**:

I would expect the task to be set as `executing` now that we are back in the threadpool.

**Minimal Complete Verifiable Example**:

```python
import time
from pprint import pprint
from typing import Dict

from distributed import Worker, get_client, secede, rejoin, LocalCluster, Client

def get_status_on_worker(dask_worker: Worker) -> Dict[str, str]:
"""Get the status for all tasks on the worker.

Args:
dask_worker: The current worker instance

Returns:
Status per task

"""
return {k: v.state for k, v in dask_worker.tasks.items()}

def subfunction_a(a: int):
# A very complicated subfunction
time.sleep(3)
return a * .5

def function_a(a: int):
# Some work that call a subfunction and secede to do so.
time.sleep(1)
secede()
print("Secede")
client = get_client()
future = client.submit(subfunction_a, a=a)
res = future.result()
print("Rejoin")
rejoin()
time.sleep(1)
print("Returning")
return res + a

def main():
cluster = LocalCluster(n_workers=2)
client = Client(cluster)
future_a = client.submit(function_a, a=3)
while not future_a.done():
status = client.run(get_status_on_worker)
pprint(status.values())
time.sleep(0.5)
status = client.run(get_status_on_worker)
pprint(status.values())

if __name__ == '__main__':
main()

```

**Anything else we need to know?**:

The output of the above script is:

```bash
dict_values([{'function_a-def6e2e640c732893a96e209971eca45': 'executing'}, {}])
dict_values([{'function_a-def6e2e640c732893a96e209971eca45': 'executing'}, {}])
Secede
dict_values([{'function_a-def6e2e640c732893a96e209971eca45': 'long-running'}, {}])
dict_values([{'function_a-def6e2e640c732893a96e209971eca45': 'long-running'}, {'subfunction_a-1d2f61ee529bf2a9b1794500a1ef9033': 'executing'}])
dict_values([{'function_a-def6e2e640c732893a96e209971eca45': 'long-running'}, {'subfunction_a-1d2f61ee529bf2a9b1794500a1ef9033': 'executing'}])
dict_values([{'function_a-def6e2e640c732893a96e209971eca45': 'long-running'}, {'subfunction_a-1d2f61ee529bf2a9b1794500a1ef9033': 'executing'}])
dict_values([{'function_a-def6e2e640c732893a96e209971eca45': 'long-running'}, {'subfunction_a-1d2f61ee529bf2a9b1794500a1ef9033': 'executing'}])
dict_values([{'function_a-def6e2e640c732893a96e209971eca45': 'long-running'}, {'subfunction_a-1d2f61ee529bf2a9b1794500a1ef9033': 'executing'}])
dict_values([{'function_a-def6e2e640c732893a96e209971eca45': 'long-running'}, {'subfunction_a-1d2f61ee529bf2a9b1794500a1ef9033': 'executing'}])
Rejoin
dict_values([{'function_a-def6e2e640c732893a96e209971eca45': 'long-running'}, {'subfunction_a-1d2f61ee529bf2a9b1794500a1ef9033': 'memory'}])
dict_values([{'function_a-def6e2e640c732893a96e209971eca45': 'long-running'}, {'subfunction_a-1d2f61ee529bf2a9b1794500a1ef9033': 'memory'}])
Returning
[{'function_a-def6e2e640c732893a96e209971eca45': 'memory'}, {}]
```

I would expect that after the "Rejoin" log, the state of `'function_a-def6e2e640c732893a96e209971eca45'` be `executing` again.

**Environment**:

- Dask version: "2021.10.0"
- Python version: 3.8
- Operating System: Mac
- Install method (conda, pip, source): pip