patch 8.0.1667: terminal window tests are flaky

Problem:    Terminal window tests are flaky.
Solution:   Increase the waiting time for Vim to start.

src/testdir/screendump.vim

@@ -59,8 +59,9 @@ func RunVimInTerminal(arguments, options)
   let buf = term_start(cmd, {'curwin': 1, 'term_rows': rows, 'term_cols': cols})
   call assert_equal([rows, cols], term_getsize(buf))
 
-  " Wait for the ruler (in the status line) to be shown.
-  call WaitFor({-> len(term_getline(buf, rows)) >= cols - 1})
+  " Wait for "All" of the ruler in the status line to be shown.
+  " This can be quite slow (e.g. when using valgrind), wait up to 4 seconds.
+  call WaitFor({-> len(term_getline(buf, rows)) >= cols - 1}, 4000)
 
   return buf
 endfunc

src/version.c

@@ -762,6 +762,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1667,
 /**/
     1666,
 /**/