patch 8.0.1771: in tests, when WaitFor() fails it doesn't say why

Problem:    In tests, when WaitFor() fails it doesn't say why. (James McCoy)
Solution:   Add WaitForAssert(), which produces an assert error when it fails.
diff --git a/src/version.c b/src/version.c
index a824e8d..c7637a3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1771,
+/**/
     1770,
 /**/
     1769,