ARROW-17930: [CI][C++] Valgrind failure in PrintValue<arrow::dataset::ScannerTestParams> (#14317)
ARROW-17930: [CI][C++] Valgrind failure in PrintValue<arrow::dataset::ScannerTestParams> (#14317)

Addresses [ARROW-17930](https://issues.apache.org/jira/browse/ARROW-17930).

Not terribly obvious, but this seems to fix the issue.

Authored-by: benibus <d08e01f101040449b91a3dd8b1a270ebdf8d966d@gmx.com>
Signed-off-by: David Li <dc24f9cfc84fb1675ce65c8444a2c3e2f0e5f297@gmail.com>
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