patch 9.0.0363: common names in test files causes tests to be flaky

Problem:    Common names in test files causes tests to be flaky.
Solution:   Use more specific names.
diff --git a/src/testdir/test_terminal2.vim b/src/testdir/test_terminal2.vim
index a40fc84..6e70ad6 100644
--- a/src/testdir/test_terminal2.vim
+++ b/src/testdir/test_terminal2.vim
@@ -415,11 +415,11 @@
   \ ]
 
   for c in contents
-    call writefile(c, 'Xfile')
+    call writefile(c, 'Xdntfile')
     if has('win32')
-      term cmd /c type Xfile
+      term cmd /c type Xdntfile
     else
-      term cat Xfile
+      term cat Xdntfile
     endif
     let bnr = bufnr('$')
     call assert_equal('terminal', getbufvar(bnr, '&buftype'))
@@ -429,7 +429,7 @@
     quit
   endfor
 
-  call delete('Xfile')
+  call delete('Xdntfile')
 endfunc
 
 func GetDummyCmd()