patch 8.2.1013: channel tests can be a bit flaky

Problem:    Channel tests can be a bit flaky.
Solution:   Set the g:test_is_flaky flag in SetUp().

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1013,
 /**/
     1012,
 /**/