Fix use of trusted code in variant task

[jonathanmetzman]

at .wrapper ( /mnt/scratch0/clusterfuzz/src/third_party/google/cloud/ndb/_options.py:89 )
at .get_fuzz_target ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/datastore/data_types.py:727 )
at .test_for_crash_with_retries ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/bot/testcase_manager.py:783 )
at .utask_main ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/bot/tasks/utasks/variant_task.py:151 )