patch 8.2.2399: fold test fails in wide terminal

Problem:    Fold test fails in wide terminal.
Solution:   Adjust the test. (Dominique Pelle, closes #7731, closes #7739)

src/testdir/test_fold.vim

@@ -864,7 +864,7 @@ func Test_fold_relative_move()
   set fdm=indent sw=2 wrap tw=80
 
   let content = [ '  foo', '  bar', '  baz',
-              \   repeat('x', 100),
+              \   repeat('x', &columns + 1),
               \   '  foo', '  bar', '  baz'
               \ ]
   call append(0, content)

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2399,
 /**/
     2398,
 /**/