test: retry streaming tests to accommodate flakiness (#956)

* test: retry streaming tests to accommodate flakiness

* reduce delay, increase retries

Author: shobsi

tests/system/large/test_streaming.py

@@ -14,10 +14,13 @@
 
 import time
 
+import pytest
+
 import bigframes
 import bigframes.streaming
 
 
+@pytest.mark.flaky(retries=3, delay=10)
 def test_streaming_df_to_bigtable(session_load: bigframes.Session):
     # launch a continuous query
     job_id_prefix = "test_streaming_"
@@ -51,6 +54,7 @@ def test_streaming_df_to_bigtable(session_load: bigframes.Session):
         query_job.cancel()
 
 
+@pytest.mark.flaky(retries=3, delay=10)
 def test_streaming_df_to_pubsub(session_load: bigframes.Session):
     # launch a continuous query
     job_id_prefix = "test_streaming_pubsub_"