patch 8.2.4121: Visual test fails on MS-Windows

Problem:    Visual test fails on MS-Windows.
Solution:   Set 'isprint' so that the character used is not printable.
diff --git a/src/testdir/test_visual.vim b/src/testdir/test_visual.vim
index 9ca0fa9..b438fa1 100644
--- a/src/testdir/test_visual.vim
+++ b/src/testdir/test_visual.vim
@@ -1280,11 +1280,13 @@
 
 func Test_visual_block_append_invalid_char()
   " this was going over the end of the line
+  set isprint=@,161-255
   new
   call setline(1, ['	   let xxx', 'xxxxxˆ', 'xxxxxxxxxxx'])
   exe "normal 0\<C-V>jjA-\<Esc>"
   call assert_equal(['	-   let xxx', 'xxxxx   -ˆ', 'xxxxxxxx-xxx'], getline(1, 3))
   bwipe!
+  set isprint&
 endfunc
 
 func Test_visual_reselect_with_count()
diff --git a/src/version.c b/src/version.c
index 6fda77e..bc75522 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4121,
+/**/
     4120,
 /**/
     4119,