patch 8.1.0652: freeing memory for balloon eval too early

Problem:    Freeing memory for balloon eval too early.
Solution:   Store the pointer in BalloonEval and free it later. (Yasuhiro
            Matsumoto, closes #3725)
diff --git a/src/version.c b/src/version.c
index 3082c0d..1579dec 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    652,
+/**/
     651,
 /**/
     650,