storage: intent resolution incorrectly updates intents with ignored seq nums

[miraradeva]

Describe the problem

The logic in mvccResolveWriteIntent was structured in such a way that if an intent contained both ignored and non-ignored seq nums in its intent history, the intent may end up being updated instead of aborted or unmodified.

To Reproduce

For the following examples, assume the intent has a history ["a", "b"] where "a" is written first, and "b" is ignored.

1. The intent resolution has status aborted. Instead of aborting the intent, it is modified to have value "a" and an empty intent history.

2. The intent resolution has status pending, and the intent has a lower epoch than the resolution. The intent should be aborted because the new epoch may not write it again. Instead, it is updated with value "a" and an empty intent history.

3. Same as 2 but the intent resolution has status committed.

4. The intent resolution has status pending, the intent is not pushed and has a higher epoch than the resolution. The intent should not be updated because the intent history is updated only when the epochs match. Instead, it is updated with value "a" and an empty intent history.

5. Same as 4 but the intent is pushed. The intent should be updated to bump its timestamp in order to unblock the pusher. The intent history should not be updated for the same reason as in 3. Instead, the intent is updated with value "a" and an empty intent history.

Additionally, in cases 1, 2, 3 and 4 above, the resulting intent is not committed but a MVCCCommitIntentOp is logged erroneously.

Additional context
This has most likely been an issue since the ignored seq nums were introduced into the MVCC code in f6a4dc5.

Jira issue: CRDB-35245