Fix CopyMultipleTablesIT(sponge_log).testCopyMultipleTables integration test failure #1805

com.google.common.truth.AssertionErrorWithFacts:
expected to contain:
    Table copied successfully.
but was:
    Table created successfully
    Table copying job was interrupted.
    com.google.cloud.bigquery.BigQueryException: An internal error occurred and the request could not be completed. This is usually caused by a transient issue. Retrying the job with back-off as described in the BigQuery SLA should solve the problem: https://cloud.google.com/bigquery/sla. If the error continues to occur please contact support at https://cloud.google.com/support. Error: 5465921

	at com.example.bigquery.CopyMultipleTablesIT.testCopyMultipleTables(CopyMultipleTablesIT.java:77)