Fix given_large_bodies_when_appending_then_wal_records_should_coalesce_into_one_barrier_group

**After #4132 is merged.**

Each test below carries its reason in the `#[ignore]` attribute and its doc comment.

| Test | Location |
|---|---|
| `given_large_bodies_when_appending_then_wal_records_should_coalesce_into_one_barrier_group` | `core/simulator/src/storage/tests.rs:2662` |

```
cargo test -p simulator --lib given_large_bodies -- --ignored
```

Remove the `#[ignore]` once it passes.

After #4132 is merged, start at core/simulator/src/storage/tests.rs:2662 and read the test's #[ignore] reason and doc comment. Run cargo test -p simulator --lib given_large_bodies -- --ignored, then remove #[ignore] once the test passes.

Written by the indexing model from the issue text.