patch 8.1.0769: :stop is covered in two tests

Problem:    :stop is covered in two tests.
Solution:   Remove Test_stop_in_terminal().  Make other test exit Vim cleanly.
            (Ozaki Kiichi, closes #3814)

src/testdir/test_suspend.vim

@@ -45,7 +45,11 @@ func Test_suspend()
   call term_sendkeys(buf, "fg\<CR>")
   call WaitForAssert({-> assert_equal('  1 foo', term_getline(buf, '.'))})
 
+  " Quit gracefully to dump coverage information.
+  call term_sendkeys(buf, ":qall!\<CR>")
+  call term_wait(buf)
+  call Stop_shell_in_terminal(buf)
+
   exe buf . 'bwipe!'
   call delete('Xfoo')
-  set autowrite&
 endfunc