patch 8.1.1084: cannot delete a match from another window

Problem:    Cannot delete a match from another window. (Paul Jolly)
Solution:   Add window ID argument to matchdelete(), clearmatches(),
            getmatches() and setmatches(). (Andy Massimino, closes #4178)
diff --git a/src/testdir/test_match.vim b/src/testdir/test_match.vim
index 94bca9a..51c9016 100644
--- a/src/testdir/test_match.vim
+++ b/src/testdir/test_match.vim
@@ -205,6 +205,19 @@
   call assert_equal(screenattr(1,2), screenattr(2,2))
   call assert_notequal(screenattr(1,2), screenattr(1,4))
 
+  let savematches = getmatches(winid)
+  let expect = [
+        \ {'group': 'Search', 'pattern': '4', 'priority': 10, 'id': 4},
+        \ {'group': 'Error', 'id': 5, 'priority': 10, 'pos1': [1, 2, 1], 'pos2': [2, 2, 1]},
+        \]
+  call assert_equal(expect, savematches)
+
+  call clearmatches(winid)
+  call assert_equal([], getmatches(winid))
+
+  call setmatches(savematches, winid)
+  call assert_equal(expect, savematches)
+
   wincmd w
   bwipe!
   call clearmatches()