patch 8.2.0937: asan failure in the flatten() test

Problem:    Asan failure in the flatten() test.
Solution:   Free the flattened list.
diff --git a/src/version.c b/src/version.c
index 37a43aa..922ab46 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    937,
+/**/
     936,
 /**/
     935,