patch 8.2.5100: memory usage tests are not retried

Problem:    Memory usage tests are not retried.
Solution:   Mark memory usage tests as flaky.
diff --git a/src/version.c b/src/version.c
index e9cfe7c..74e8595 100644
--- a/src/version.c
+++ b/src/version.c
@@ -735,6 +735,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    5100,
+/**/
     5099,
 /**/
     5098,