patch 8.2.3707: Vim9: constant expression of elseif not recognized

Problem:    Vim9: constant expression of elseif not recognized.
Solution:   Set instruction count before generating the expression.
diff --git a/src/version.c b/src/version.c
index 601055a..e29cb31 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3707,
+/**/
     3706,
 /**/
     3705,