patch 8.1.1741: cleared/added match highlighting not updated in other window

Problem:    Cleared/added match highlighting not updated in other window.
            (Andi Massimino)
Solution:   Mark the right window for refresh.
diff --git a/src/testdir/test_match.vim b/src/testdir/test_match.vim
index 07005b5..8eada3f 100644
--- a/src/testdir/test_match.vim
+++ b/src/testdir/test_match.vim
@@ -253,25 +253,54 @@
   set hlsearch&
 endfunc
 
-func Test_matchdelete_other_window()
-  if !CanRunVimInTerminal()
-    throw 'Skipped: cannot make screendumps'
-  endif
-
+func OtherWindowCommon()
   let lines =<< trim END
     call setline(1, 'Hello Vim world')
     let mid = matchadd('Error', 'world', 1)
     let winid = win_getid()
     new
   END
-  call writefile(lines, 'XscriptMatchDelete')
-  let buf = RunVimInTerminal('-S XscriptMatchDelete', #{rows: 12})
+  call writefile(lines, 'XscriptMatchCommon')
+  let buf = RunVimInTerminal('-S XscriptMatchCommon', #{rows: 12})
   call term_wait(buf)
+  return buf
+endfunc
+
+func Test_matchdelete_other_window()
+  if !CanRunVimInTerminal()
+    throw 'Skipped: cannot make screendumps'
+  endif
+  let buf = OtherWindowCommon()
   call term_sendkeys(buf, ":call matchdelete(mid, winid)\<CR>")
   call VerifyScreenDump(buf, 'Test_matchdelete_1', {})
 
   call StopVimInTerminal(buf)
-  call delete('XscriptMatchDelete')
+  call delete('XscriptMatchCommon')
+endfunc
+
+func Test_matchclear_other_window()
+  if !CanRunVimInTerminal()
+    throw 'Skipped: cannot make screendumps'
+  endif
+  let buf = OtherWindowCommon()
+  call term_sendkeys(buf, ":call clearmatches(winid)\<CR>")
+  call VerifyScreenDump(buf, 'Test_matchclear_1', {})
+
+  call StopVimInTerminal(buf)
+  call delete('XscriptMatchCommon')
+endfunc
+
+func Test_matchadd_other_window()
+  if !CanRunVimInTerminal()
+    throw 'Skipped: cannot make screendumps'
+  endif
+  let buf = OtherWindowCommon()
+  call term_sendkeys(buf, ":call matchadd('Search', 'Hello', 1, -1, #{window: winid})\<CR>")
+  call term_sendkeys(buf, ":\<CR>")
+  call VerifyScreenDump(buf, 'Test_matchadd_1', {})
+
+  call StopVimInTerminal(buf)
+  call delete('XscriptMatchCommon')
 endfunc