In `transactions_target_at_point_in_time.js`, we run transactions with `snapshot` read concern. On slow machines, if the transaction takes a long time, we can see the transaction read operation fail with `SnapshotTooOld`, because the default snapshot history window is only 5s.

In 4.4, we don't have the ability to set the minimum snapshot history window via server parameter. Instead, we can use the failpoint `WTPreserveSnapshotHistoryIndefinitely` to preserve the history for the duration of the test, so that even slow transactions complete.

We've implemented a similar solution for other 4.4 tests that fail due to insufficient snapshot history (like SERVER-42025). This fix should also only go in v4.4, as we've fixed the issue on v5.0 and above with the usage of a server parameter.