patch 8.1.1860: map timeout test is flaky

Problem:    Map timeout test is flaky.
Solution:   Add test to list of flaky tests.  Increase timeout.

src/testdir/runtest.vim

@@ -322,6 +322,7 @@ let s:flaky_tests = [
       \ 'Test_diff_screen()',
       \ 'Test_exit_callback()',
       \ 'Test_exit_callback_interval()',
+      \ 'Test_map_timeout_with_timer_interrupt()',
       \ 'Test_nb_basic()',
       \ 'Test_open_delay()',
       \ 'Test_out_cb()',

src/testdir/test_mapping.vim

@@ -298,7 +298,7 @@ func Test_map_timeout_with_timer_interrupt()
   let g:val = 0
   nnoremap \12 :let g:val = 1<CR>
   nnoremap \123 :let g:val = 2<CR>
-  set timeout timeoutlen=100
+  set timeout timeoutlen=200
 
   func ExitCb(job, status)
     let g:timer = timer_start(1, {-> feedkeys("3\<Esc>", 't')})

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1860,
 /**/
     1859,
 /**/