Eventual-send types should map the result

[mhofman]

What is the Problem Being Solved?

Currently the result of an eventual-send is simply a promise for the original result of the callable. For results that document a "local remotable" that isn't actually correct as the eventual-send may not be local, and as such the remotable would only show up as a "remote presence".

Passing through the original type for anything remotable risks the consumer potentially await-ing the result and attempt to directly interact with the remotable as the static type currently implies.

Description of the Design

#2849 introduced and EAwaitedResult that does this mapping (as much as possible), but it couldn't be adopted in E types itself as it broke some cases in agoric-sdk. There may be some relations to #2979, where keeping only the nominal RemotableBrand may break some checks for "passable" RemotableObject. I also remember some issues with the tagged containers helpers used for Instance handles in agoric-sdk.

Security Considerations

None, type only

Test Plan

We need some type tests in endo that sufficiently cover all the advanced types and inference agoric-sdk relies on.

Compatibility Considerations

This change will rely on consumers to adapt to stricter types, but shouldn't cause a loss of type coverage, or make it impossible to adapt.

Upgrade Considerations

Types only