test_multi_triggered_gbk_side_input is always using DirectRunner

The option provided in the test overwrite the argument provided during validates runner test

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FAIL: Test a GBK sideinput, with multiple triggering.
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Traceback (most recent call last):
File "/usr/local/google/home/goenka/d/work/beam/beam/sdks/python/apache_beam/transforms/sideinputs_test.py", line 401, in test_multi_triggered_gbk_side_input
p.run()
File "/usr/local/google/home/goenka/d/work/beam/beam/sdks/python/apache_beam/testing/test_pipeline.py", line 112, in run
False if self.not_use_test_runner_api else test_runner_api))
File "/usr/local/google/home/goenka/d/work/beam/beam/sdks/python/apache_beam/pipeline.py", line 483, in run
self._options).run(False)
File "/usr/local/google/home/goenka/d/work/beam/beam/sdks/python/apache_beam/pipeline.py", line 809, in from_runner_api
p.transforms_stack = [context.transforms.get_by_id(root_transform_id)]
File "/usr/local/google/home/goenka/d/work/beam/beam/sdks/python/apache_beam/runners/pipeline_context.py", line 103, in get_by_id
self._id_to_proto[id], self._pipeline_context)
File "/usr/local/google/home/goenka/d/work/beam/beam/sdks/python/apache_beam/pipeline.py", line 1117, in from_runner_api
part = context.transforms.get_by_id(transform_id)
File "/usr/local/google/home/goenka/d/work/beam/beam/sdks/python/apache_beam/runners/pipeline_context.py", line 103, in get_by_id
self._id_to_proto[id], self._pipeline_context)
File "/usr/local/google/home/goenka/d/work/beam/beam/sdks/python/apache_beam/pipeline.py", line 1104, in from_runner_api
transform = ptransform.PTransform.from_runner_api(proto, context)
File "/usr/local/google/home/goenka/d/work/beam/beam/sdks/python/apache_beam/transforms/ptransform.py", line 684, in from_runner_api
context)
File "/usr/local/google/home/goenka/d/work/beam/beam/sdks/python/apache_beam/testing/test_stream.py", line 316, in from_runner_api_parameter
output_tags=output_tags)
File "/usr/local/google/home/goenka/d/work/beam/beam/sdks/python/apache_beam/testing/test_stream.py", line 200, in __init__
assert event_tags.issubset(self.output_tags)
AssertionError:
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root: INFO: Missing pipeline option (runner). Executing pipeline using the default runner: DirectRunner.
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Imported from Jira [BEAM-9402](https://issues.apache.org/jira/browse/BEAM-9402). Original Jira may contain additional context.
Reported by: angoenka.