patch 8.0.0288: errors reported while running tests

Problem:    Errors reported while running tests.
Solution:   Put comma in the right place.

src/testdir/runtest.vim

@@ -158,7 +158,7 @@ let s:flaky = [
       \ 'Test_communicate()',
       \ 'Test_nb_basic()',
       \ 'Test_pipe_through_sort_all()',
-      \ 'Test_pipe_through_sort_some()'
+      \ 'Test_pipe_through_sort_some()',
       \ 'Test_reltime()',
       \ ]
 

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    288,
 /**/
     287,
 /**/