patch 8.1.0471: some tests are flaky or fail on some systems

Problem:    Some tests are flaky or fail on some systems.
Solution:   Increase waiting time for port number. Use "cmd /c" to execute
            "echo" on win32. (Ken Takata, closes #3534)

src/testdir/shared.vim

@@ -49,7 +49,8 @@ endfunc
 " Read the port number from the Xportnr file.
 func GetPort()
   let l = []
-  for i in range(200)
+  " with 200 it sometimes failed
+  for i in range(400)
     try
       let l = readfile("Xportnr")
     catch
@@ -274,6 +275,10 @@ func GetVimCommandClean()
   let cmd = GetVimCommand()
   let cmd = substitute(cmd, '-u NONE', '--clean', '')
   let cmd = substitute(cmd, '--not-a-term', '', '')
+
+  " Optionally run Vim under valgrind
+  " let cmd = 'valgrind --tool=memcheck --leak-check=yes --num-callers=25 --log-file=valgrind ' . cmd
+
   return cmd
 endfunc
 

src/testdir/test_channel.vim

@@ -1340,7 +1340,7 @@ func Test_close_and_exit_cb()
     let self.ret['exit_cb'] = job_status(a:job)
   endfunc
 
-  let g:job = job_start('echo', {
+  let g:job = job_start(has('win32') ? 'cmd /c echo:' : 'echo', {
         \ 'close_cb': g:retdict.close_cb,
         \ 'exit_cb': g:retdict.exit_cb,
         \ })
@@ -1369,7 +1369,8 @@ func Test_exit_cb_wipes_buf()
   new
   let g:wipe_buf = bufnr('')
 
-  let job = job_start(['true'], {'exit_cb': 'ExitCbWipe'})
+  let job = job_start(has('win32') ? 'cmd /c echo:' : ['true'],
+			  \ {'exit_cb': 'ExitCbWipe'})
   let timer = timer_start(300, {-> feedkeys("\<Esc>", 'nt')}, {'repeat': 5})
   call feedkeys(repeat('g', 1000) . 'o', 'ntx!')
   call WaitForAssert({-> assert_equal("dead", job_status(job))})

src/version.c

@@ -792,6 +792,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    471,
 /**/
     470,
 /**/