patch 8.2.0786: channel test is flaky on FreeBSD

Problem:    Channel test is flaky on FreeBSD.
Solution:   Set the sockiet TCP_NODELAY option. Adjust expected line count in
            netbeans test. (Ozaki Kiichi, closes #6097)

src/testdir/test_channel.py

@@ -21,6 +21,9 @@ except ImportError:
 
 class ThreadedTCPRequestHandler(socketserver.BaseRequestHandler):
 
+    def setup(self):
+        self.request.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
+
     def handle(self):
         print("=== socket opened ===")
         while True:

src/testdir/test_netbeans.vim

@@ -609,7 +609,7 @@ func Nb_basic(port)
 
   " detach
   call appendbufline(cmdbufnr, '$', 'detach_Test')
-  call WaitFor('len(readfile("Xnetbeans")) >= (g:last + 6)')
+  call WaitFor('len(readfile("Xnetbeans")) >= (g:last + 8)')
   call WaitForAssert({-> assert_equal('0:disconnect=91', readfile("Xnetbeans")[-1])})
 
   " the connection was closed

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    786,
 /**/
     785,
 /**/