patch 8.0.1631: testing with Vim running in terminal is a bit flaky

Problem:    Testing with Vim running in terminal is a bit flaky.
Solution:   Delete any .swp file so that later tests don't fail.

src/testdir/screendump.vim

@@ -26,6 +26,10 @@ source shared.vim
 "
 " Options is a dictionary (not used yet).
 func RunVimInTerminal(arguments, options)
+  " If Vim doesn't exit a swap file remains, causing other tests to fail.
+  " Remove it here.
+  call delete(".swp")
+
   " Make a horizontal and vertical split, so that we can get exactly the right
   " size terminal window.  Works only when we currently have one window.
   call assert_equal(1, winnr('$'))

src/version.c

@@ -766,6 +766,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1631,
 /**/
     1630,
 /**/