GoTest: Output original message on failure return code

When using jobcontrol, assume FAILED if return code is >0. Only prints the first line.

autoload/go/cmd.vim

@@ -195,6 +195,9 @@ function! go#cmd#Test(bang, compile, ...)
         call go#list#Window(len(errors))
         if !empty(errors) && !a:bang
             call go#list#JumpToFirst()
+        elseif empty(errors)
+            " failed to parse errors, output the original content
+            call go#util#EchoError(out)
         endif
         echon "vim-go: " | echohl ErrorMsg | echon "[test] FAIL" | echohl None
     else

autoload/go/jobcontrol.vim

@@ -93,28 +93,25 @@ endfunction
 " it'll be closed.
 function! s:on_exit(job_id, data)
   let std_combined = self.stderr + self.stdout
-  if empty(std_combined)
+  if a:data == 0
     call go#list#Clean()
     call go#list#Window()
 
     let self.state = "SUCCESS"
     return
   endif
 
+  let self.state = "FAILED"
+
   let errors = go#tool#ParseErrors(std_combined)
   let errors = go#tool#FilterValids(errors)
 
   if !len(errors)
-    " no errors could be past, just return
-    call go#list#Clean()
-    call go#list#Window()
-
-    let self.state = "SUCCESS"
+    " failed to parse errors, output the original content
+    call go#util#EchoError(std_combined[0])
     return
   endif
 
-  let self.state = "FAILED"
-
   " if we are still in the same windows show the list
   if self.winnr == winnr()
     call go#list#Populate(errors)