WT-9466 changed the way try_rollback works and tests are not behaving the way they used too.

Now, try_rollback rolls back if a transaction is active. Before, it used to rollback if a transaction was active and the number of executed operations reached the target. With the current implementation, the default read_operation only reads the first key, rolls back and does the same again until the test ends. In other words, we are missing the rest of the keys, only the first one is solicited.

This ticket should fix the existing tests to restore them to their previous behaviour.