[Bug]: ParDo#with_exception_handling(use_subprocess=True) doesn't work because of missing _context.process_instruction_id

### What happened?

Using `ParDo#with_exception_handling(use_subprocess=True)` seems to fail because it relies on `_context.process_instruction_id` which doesn't exist in the process.

```
Traceback (most recent call last):
File "/data_gen_docker_pybinary.runfiles/python3_x86_64/lib/python3.7/multiprocessing/queues.py", line 236, in _feed
obj = _ForkingPickler.dumps(obj)
File "/data_gen_docker_pybinary.runfiles/python3_x86_64/lib/python3.7/multiprocessing/reduction.py", line 51, in dumps
cls(buf, protocol).dump(obj)
File "apache_beam/coders/coder_impl.py", line 1035, in apache_beam.coders.coder_impl._ConcatSequence.__reduce__
File "apache_beam/coders/coder_impl.py", line 1025, in __iter__
File "/data_gen_docker_pybinary.runfiles/cruise_ws/cruise/mlp/cfs/projects/trajectory_ranking/pipeline/data_gen_docker_pybinary_exedir/apache_beam/runners/worker/sdk_worker.py", line 1184, in _lazy_iterator
self._underlying.get_raw(state_key, continuation_token))
File "/data_gen_docker_pybinary.runfiles/cruise_ws/cruise/mlp/cfs/projects/trajectory_ranking/pipeline/data_gen_docker_pybinary_exedir/apache_beam/runners/worker/sdk_worker.py", line 986, in get_raw
continuation_token=continuation_token)))
File "/data_gen_docker_pybinary.runfiles/cruise_ws/cruise/mlp/cfs/projects/trajectory_ranking/pipeline/data_gen_docker_pybinary_exedir/apache_beam/runners/worker/sdk_worker.py", line 1019, in _blocking_request
req_future = self._request(request)
File "/data_gen_docker_pybinary.runfiles/cruise_ws/cruise/mlp/cfs/projects/trajectory_ranking/pipeline/data_gen_docker_pybinary_exedir/apache_beam/runners/worker/sdk_worker.py", line 1009, in _request
request.instruction_id = self._context.process_instruction_id
AttributeError: \'_thread._local\' object has no attribute \'process_instruction_id\'
"""
', '
The above exception was the direct cause of the following exception:

', 'Traceback (most recent call last):
', ' File "/data_gen_docker_pybinary.runfiles/cruise_ws/cruise/mlp/cfs/projects/trajectory_ranking/pipeline/data_gen_docker_pybinary_exedir/apache_beam/transforms/core.py", line 1895, in process
result = self._fn.process(*args, **kwargs)
', ' File "/data_gen_docker_pybinary.runfiles/cruise_ws/cruise/mlp/cfs/projects/trajectory_ranking/pipeline/data_gen_docker_pybinary_exedir/apache_beam/transforms/core.py", line 1933, in process
return self._call_remote(self._remote_process, *args, **kwargs)
', ' File "/data_gen_docker_pybinary.runfiles/cruise_ws/cruise/mlp/cfs/projects/trajectory_ranking/pipeline/data_gen_docker_pybinary_exedir/apache_beam/transforms/core.py", line 1948, in _call_remote
return self._pool.submit(method, *args, **kwargs).result()
', ' File "/data_gen_docker_pybinary.runfiles/python3_x86_64/lib/python3.7/concurrent/futures/_base.py", line 432, in result
return self.__get_result()
', ' File "/data_gen_docker_pybinary.runfiles/python3_x86_64/lib/python3.7/concurrent/futures/_base.py", line 384, in __get_result
raise self._exception
', ' File "/data_gen_docker_pybinary.runfiles/python3_x86_64/lib/python3.7/multiprocessing/queues.py", line 236, in _feed
obj = _ForkingPickler.dumps(obj)
', ' File "/data_gen_docker_pybinary.runfiles/python3_x86_64/lib/python3.7/multiprocessing/reduction.py", line 51, in dumps
cls(buf, protocol).dump(obj)
', ' File "apache_beam/coders/coder_impl.py", line 1035, in apache_beam.coders.coder_impl._ConcatSequence.__reduce__
', ' File "apache_beam/coders/coder_impl.py", line 1025, in __iter__
', ' File "/data_gen_docker_pybinary.runfiles/cruise_ws/cruise/mlp/cfs/projects/trajectory_ranking/pipeline/data_gen_docker_pybinary_exedir/apache_beam/runners/worker/sdk_worker.py", line 1184, in _lazy_iterator
self._underlying.get_raw(state_key, continuation_token))
', ' File "/data_gen_docker_pybinary.runfiles/cruise_ws/cruise/mlp/cfs/projects/trajectory_ranking/pipeline/data_gen_docker_pybinary_exedir/apache_beam/runners/worker/sdk_worker.py", line 986, in get_raw
continuation_token=continuation_token)))
', ' File "/data_gen_docker_pybinary.runfiles/cruise_ws/cruise/mlp/cfs/projects/trajectory_ranking/pipeline/data_gen_docker_pybinary_exedir/apache_beam/runners/worker/sdk_worker.py", line 1019, in _blocking_request
req_future = self._request(request)
', ' File "/data_gen_docker_pybinary.runfiles/cruise_ws/cruise/mlp/cfs/projects/trajectory_ranking/pipeline/data_gen_docker_pybinary_exedir/apache_beam/runners/worker/sdk_worker.py", line 1009, in _request
request.instruction_id = self._context.process_instruction_id
', "AttributeError: '_thread._local' object has no attribute 'process_instruction_id'
```

I will come up with reproducible example

### Issue Priority

Priority: 2 (default / most bugs should be filed as P2)

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