patch 8.0.0400: some tests have a one second delay

Problem:    Some tests have a one second delay.
Solution:   Add --not-a-term in RunVim().

src/testdir/shared.vim

@@ -192,6 +192,7 @@ func RunVimPiped(before, after, arguments, pipecmd)
   if cmd !~ '-u NONE'
     let cmd = cmd . ' -u NONE'
   endif
+  let cmd .= ' --not-a-term'
 
   " With pipecmd we can't set VIMRUNTIME.
   if a:pipecmd != ''

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    400,
 /**/
     399,
 /**/