Found while investigating #42250.

The comment on this test says:

// Test that a write with a higher epoch is permitted even when the sequence
// number has decreased compared to an existing intent. This is because, on
// transaction restart, the sequence number should not be compared with intents
// from the old epoch.
// Additionally the intent history is blown away when a transaction restarts.

The problem with the last sentence is that the test ever only issues a single MVCCPut, so it does not generate an intent history to start with. Therefore, the check that the intent history disappears upon restart does not actually test anything.