Add a `TaggedQueryKey` to identify a query instance
This adds back a `TaggedQueryKey` enum which represents a query kind and the associated key. This is used to replace `QueryStackDeferred` and `QueryStackFrameExtra` and the associated lifting operation for cycle errors
This approach has a couple of benefits:
- We only run description queries when printing the query stack trace in the panic handler
- The unsafe code for `QueryStackDeferred` is removed
- Cycle handles have access to query keys, which may be handy
Some further work could be replacing `QueryStackFrame` with `TaggedQueryKey` as the extra information can be derived from it.
Stuart Cook
aa2efbc60a