patch 8.2.2149: popupwin test for latin1 sometimes fails

Problem:    Popupwin test for latin1 sometimes fails.
Solution:   Wait for the script to finish.

Author: brammool

src/testdir/test_popupwin.vim

@@ -3721,11 +3721,14 @@ func Test_popupwin_latin1_encoding()
       set encoding=latin1
       terminal cat Xmultibyte
       call popup_create(['one', 'two', 'three', 'four'], #{line: 1, col: 10})
+      redraw
+      echo "Done"
   END
   call writefile(lines, 'XtestPopupLatin')
   call writefile([repeat("\u3042 ", 120)], 'Xmultibyte')
 
   let buf = RunVimInTerminal('-S XtestPopupLatin', #{rows: 10})
+  call WaitForAssert({-> assert_match('Done', term_getline(buf, 10))})
 
   call term_sendkeys(buf, ":q\<CR>")
   call StopVimInTerminal(buf)

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2149,
 /**/
     2148,
 /**/