Errors reported from malformed builtin calls are handled in a later
    pass than the one in which they are detected.  If a malformed builtin
    call is lowered into an error expression too early, these errors will
    never be reported.
    
    Fixes golang/go#11561.
    
    Reviewed-on: https://go-review.googlesource.com/12778

From-SVN: r226459