metamorphic: allow single deletes after range deletes

[jbowens]

Single deletes have subtle requirements for deterministic behavior. In order to exercise them within the metamorphic test, the metamorphic test tracks the operations performed against every key. It uses this history to derive whether a single delete against a particular key would be deterministic. This tracking does not account for range deletions (or the new excise operation introduced in #3044). This omission does not introduce nondeterminism within the metamorphic test, but it reduces the metamorphic test's test coverage by being more conservative than CockroachDB in its decision making.

We should adjust the metamorphic test allow testing these scenarios.

Motivated in part by cockroachdb/cockroach#114421 which could plausibly be caused by a single delete bug.