This adds ResultNames to HostFunctionBuilder and FunctionDefinition
which helps for multi-results or special-cased ones.
End users can access result names in `FunctionDefinition.ResultNames` or
set for their own host functions via
`HostFunctionBuilder.WithResultNames`. This change adds them for all
built-in functions where result names help.
Most notably, GOOS=js uses `ProxyFunc` to allow logging when a function
returns multiple results. Before, the results were returned without
names: e.g. `11231,1` and now they are named like `n=11231,ok=1`.
We soon plan to allow more visibility in WASI, for example, logging
results that will write to memory offsets. This infrastructure makes it
possible to do that.
Signed-off-by: Adrian Cole <adrian@tetrate.io>
af8105ba0e