patch 8.2.0123: complete_info() does not work when CompleteDone is triggered

Problem:    complete_info() does not work when CompleteDone is triggered.
Solution:   Trigger CompleteDone before clearing the info.
diff --git a/src/testdir/test_ins_complete.vim b/src/testdir/test_ins_complete.vim
index c9d93ce..ef5ac72 100644
--- a/src/testdir/test_ins_complete.vim
+++ b/src/testdir/test_ins_complete.vim
@@ -183,6 +183,8 @@
   call assert_equal( 'W',              v:completed_item[ 'kind' ] )
   call assert_equal( 'test',           v:completed_item[ 'user_data' ] )
 
+  call assert_equal('function', complete_info().mode)
+
   let s:called_completedone = 1
 endfunc