Errors after @async are not interactive

[rafaqz]

Found another one :)

julia> @async error()
Task (failed) @0x00007f7a83baca90

Stacktrace:
 [1] error()
   @ Base ./error.jl:42
 [2] (::var"#29#30")()
   @ Main ./task.jl:406

[MichaelHatherly]

That one may be pretty tricky to make interactive.