Add u64 ExecutionId type (#8771)
### Description
The plan for task-local Vcs is to extend the `RawVc` type into:
```
enum RawVc {
TaskOutput(TaskId),
TaskCell(TaskId, CellId),
LocalCell(ExecutionId, LocalCellId), // new variant!
}
```
Where `ExecutionId` is a globally unique value representing the current task execution. That will be used with runtime safety checks to ensure that a given `LocalCellId` (which is an index into a task-local arena/vec) is valid upon read.
https://www.notion.so/vercel/Resolved-Vcs-Vc-Lifetimes-Local-Vcs-and-Vc-Refcounts-49d666d3f9594017b5b312b87ddc5bff?pvs=4
This PR extends the `define_id` macro to support arbitrary integer types, and uses that to define `ExecutionId`.
### Testing Instructions
```
cargo nextest r -p turbo-tasks -p turbo-tasks-memory
```
