patch 8.1.0591: channel sort test is flaky

Problem:    Channel sort test is flaky.
Solution:   Do not check if the job is running, it may have be done very fast.
diff --git a/src/testdir/test_channel.vim b/src/testdir/test_channel.vim
index 072bbe0..bbc6048 100644
--- a/src/testdir/test_channel.vim
+++ b/src/testdir/test_channel.vim
@@ -922,9 +922,9 @@
     let options.in_bot = 4
   endif
   let g:job = job_start('sort', options)
-  call assert_equal("run", job_status(g:job))
 
   if !a:use_buffer
+    call assert_equal("run", job_status(g:job))
     call ch_sendraw(g:job, "ccc\naaa\nddd\nbbb\neee\n")
     call ch_close_in(g:job)
   endif
diff --git a/src/version.c b/src/version.c
index 3ea9dc6..aafd4cb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    591,
+/**/
     590,
 /**/
     589,