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)
diff --git a/src/testdir/test_netbeans.vim b/src/testdir/test_netbeans.vim
index 7f1dab4..781f179 100644
--- a/src/testdir/test_netbeans.vim
+++ b/src/testdir/test_netbeans.vim
@@ -609,7 +609,7 @@
 
   " 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