patch 8.1.1852: timers test is flaky

Problem:    Timers test is flaky.
Solution:   Accept a larger count.  Add test to list of flaky tests.

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1852,
 /**/
     1851,
 /**/