patch 8.2.5013: after text formatting cursor may be in an invalid position

Problem:    After text formatting the cursor may be in an invalid position.
Solution:   Correct the cursor position after formatting.
diff --git a/src/testdir/test_textformat.vim b/src/testdir/test_textformat.vim
index d33e250..c5f5975 100644
--- a/src/testdir/test_textformat.vim
+++ b/src/testdir/test_textformat.vim
@@ -1291,4 +1291,16 @@
   close!
 endfunc
 
+" This was leaving the cursor after the end of a line.  Complicated way to
+" have the problem show up with valgrind.
+func Test_correct_cursor_position()
+  set encoding=iso8859
+  new
+  norm a000“0
+  sil! norm gggg0i0gw0gg
+
+  bwipe!
+  set encoding=utf8
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab