patch 8.2.0400: not all tests using a terminal are in the list of flaky tests

Problem:    Not all tests using a terminal are in the list of flaky tests.
Solution:   Introduce the test_is_flaky flag.
diff --git a/src/version.c b/src/version.c
index 686e045..10ec242 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    400,
+/**/
     399,
 /**/
     398,