vim-patch:8.0.1267: Test_swap_group may leave file behind

Problem:    Test_swap_group may leave file behind.
Solution:   Add a try/finally.
5842a748be

src/nvim/testdir/test_swap.vim

@@ -60,6 +60,7 @@ func Test_swap_group()
     throw 'Skipped: need at least two groups, got ' . string(groups)
   endif
 
+  try
     call delete('Xtest')
     split Xtest
     call setline(1, 'just some text')
@@ -81,8 +82,9 @@ func Test_swap_group()
 	bwipe!
       endif
     endif
-
+  finally
     call delete('Xtest')
+  endtry
 endfunc
 
 func Test_missing_dir()

src/nvim/testdir/test_undo.vim

@@ -242,6 +242,7 @@ func Test_undojoin()
 endfunc
 
 func Test_undo_write()
+  call delete('Xtest')
   split Xtest
   call feedkeys("ione one one\<Esc>", 'xt')
   w!