patch 8.1.1234: swap file test fails on MS-Windows

Problem:    Swap file test fails on MS-Windows.
Solution:   Only compare the tail of the file names.
diff --git a/src/testdir/test_swap.vim b/src/testdir/test_swap.vim
index b6bf90c..9eda9b2 100644
--- a/src/testdir/test_swap.vim
+++ b/src/testdir/test_swap.vim
@@ -194,7 +194,7 @@
   let s:swapname = ''
   split XswapfileText
   quit
-  call assert_equal(swapfile_name, s:swapname)
+  call assert_equal(fnamemodify(swapfile_name, ':t'), fnamemodify(s:swapname, ':t'))
 
   " Write the swapfile with a modified PID, now it will be automatically
   " deleted. Process one should never be Vim.
@@ -211,7 +211,7 @@
   let s:swapname = ''
   split XswapfileText
   quit
-  call assert_equal(swapfile_name, s:swapname)
+  call assert_equal(fnamemodify(swapfile_name, ':t'), fnamemodify(s:swapname, ':t'))
 
   call delete('XswapfileText')
   call delete(swapfile_name)