Consider providing IDispatch data with trimming/AOT

For our `StandardDispatch` (which replaces `IReflect`) we're providing members via reflection (see `ClassPropertyDispatchAdapter`). If this becomes a problem with trimming/AOT, we could manually compose the known members and add any diffs in the user types. For example, `ExtenderProxy` provides its own properties and those of the `Control` it is proxying. We know the ones we define and could write manual adapters for them (or perhaps a source generator to do so).