patch 9.0.1171: screen is not redrawn after using setcellwidths()

Problem:    Screen is not redrawn after using setcellwidths().
Solution:   Redraw the screen when the cell widths have changed. (Yasuhiro
            Matsumoto, closes #11800)
diff --git a/src/mbyte.c b/src/mbyte.c
index aa2b177..1570cef 100644
--- a/src/mbyte.c
+++ b/src/mbyte.c
@@ -5742,6 +5742,7 @@
     }
 
     vim_free(cw_table_save);
+    redraw_all_later(UPD_CLEAR);
 }
 
     void
diff --git a/src/testdir/dumps/Test_setcellwidths_dump_1.dump b/src/testdir/dumps/Test_setcellwidths_dump_1.dump
new file mode 100644
index 0000000..0bb2788
--- /dev/null
+++ b/src/testdir/dumps/Test_setcellwidths_dump_1.dump
@@ -0,0 +1,6 @@
+>+0&#ffffff0|D|e|s|k|t|o|p| @66
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|,|1| @10|A|l@1| 
diff --git a/src/testdir/dumps/Test_setcellwidths_dump_2.dump b/src/testdir/dumps/Test_setcellwidths_dump_2.dump
new file mode 100644
index 0000000..f7b4b0f
--- /dev/null
+++ b/src/testdir/dumps/Test_setcellwidths_dump_2.dump
@@ -0,0 +1,6 @@
+>+0&#ffffff0| |D|e|s|k|t|o|p| @65
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|,|1| @10|A|l@1| 
diff --git a/src/testdir/test_utf8.vim b/src/testdir/test_utf8.vim
index bb99cb3..935af7e 100644
--- a/src/testdir/test_utf8.vim
+++ b/src/testdir/test_utf8.vim
@@ -2,6 +2,7 @@
  
 source check.vim
 source view_util.vim
+source screendump.vim
 
 " Visual block Insert adjusts for multi-byte char
 func Test_visual_block_insert()
@@ -198,6 +199,22 @@
   call setcellwidths([])
 endfunc
 
+func Test_setcellwidths_dump()
+  CheckRunVimInTerminal
+
+  let lines =<< trim END
+      call setline(1, "\ue5ffDesktop")
+  END
+  call writefile(lines, 'XCellwidths', 'D')
+  let buf = RunVimInTerminal('-S XCellwidths', {'rows': 6})
+  call VerifyScreenDump(buf, 'Test_setcellwidths_dump_1', {})
+
+  call term_sendkeys(buf, ":call setcellwidths([[0xe5ff, 0xe5ff, 2]])\<CR>")
+  call VerifyScreenDump(buf, 'Test_setcellwidths_dump_2', {})
+
+  call StopVimInTerminal(buf)
+endfunc
+
 func Test_print_overlong()
   " Text with more composing characters than MB_MAXBYTES.
   new
diff --git a/src/version.c b/src/version.c
index b3efaab..da397ee 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1171,
+/**/
     1170,
 /**/
     1169,