patch 8.0.1653: screen dump is made too soon

Problem:    Screen dump is made too soon.
Solution:   Wait until the ruler is displayed. (Ozaki Kiichi, closes #2755)
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index d0ef325..eac54c1 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -975,7 +975,7 @@
 func Check_dump01(off)
   call assert_equal('one two three four five', trim(getline(a:off + 1)))
   call assert_equal('~           Select Word', trim(getline(a:off + 7)))
-  call assert_equal(':popup PopUp                                   :', trim(getline(a:off + 20)))
+  call assert_equal(':popup PopUp', trim(getline(a:off + 20)))
 endfunc
 
 func Test_terminal_dumpwrite_composing()