patch 8.2.1065: Vim9: no line break allowed inside a list

Problem:    Vim9: no line break allowed inside a list.
Solution:   Handle line break inside a list in Vim9 script.
diff --git a/src/testdir/test_arglist.vim b/src/testdir/test_arglist.vim
index f9995a4..198ca98 100644
--- a/src/testdir/test_arglist.vim
+++ b/src/testdir/test_arglist.vim
@@ -175,22 +175,25 @@
 
   let save_columns = &columns
   let &columns = 79
-  exe 'args ' .. join(range(1, 81))
-  call assert_equal(join([
-        \ '',
-        \ '[1] 6   11  16  21  26  31  36  41  46  51  56  61  66  71  76  81  ',
-        \ '2   7   12  17  22  27  32  37  42  47  52  57  62  67  72  77  ',
-        \ '3   8   13  18  23  28  33  38  43  48  53  58  63  68  73  78  ',
-        \ '4   9   14  19  24  29  34  39  44  49  54  59  64  69  74  79  ',
-        \ '5   10  15  20  25  30  35  40  45  50  55  60  65  70  75  80  ',
-        \ ], "\n"),
-        \ execute('args'))
+  try
+    exe 'args ' .. join(range(1, 81))
+    call assert_equal(join([
+          \ '',
+          \ '[1] 6   11  16  21  26  31  36  41  46  51  56  61  66  71  76  81  ',
+          \ '2   7   12  17  22  27  32  37  42  47  52  57  62  67  72  77  ',
+          \ '3   8   13  18  23  28  33  38  43  48  53  58  63  68  73  78  ',
+          \ '4   9   14  19  24  29  34  39  44  49  54  59  64  69  74  79  ',
+          \ '5   10  15  20  25  30  35  40  45  50  55  60  65  70  75  80  ',
+          \ ], "\n"),
+          \ execute('args'))
 
-  " No trailing newline with one item per row.
-  let long_arg = repeat('X', 81)
-  exe 'args ' .. long_arg
-  call assert_equal("\n[".long_arg.']', execute('args'))
-  let &columns = save_columns
+    " No trailing newline with one item per row.
+    let long_arg = repeat('X', 81)
+    exe 'args ' .. long_arg
+    call assert_equal("\n[".long_arg.']', execute('args'))
+  finally
+    let &columns = save_columns
+  endtry
 
   " Setting argument list should fail when the current buffer has unsaved
   " changes