Simplify test

Author: mhauru

test/copyable_task.jl

@@ -225,9 +225,7 @@
         # Test calling a function that does something with the return value of `produce`.
         # In this case it just returns it. This used to error, see
         # https://github.com/TuringLang/Libtask.jl/issues/190.
-        produce_wrapper(x) = Libtask.produce(x)
-        Libtask.might_produce(::Type{<:Tuple{typeof(produce_wrapper),Any}}) = true
-        f(obs) = produce_wrapper(obs)
+        f(obs) = produce(obs)
         tt = Libtask.TapedTask(nothing, f, :a)
         @test Libtask.consume(tt) === :a
         @test Libtask.consume(tt) === nothing