patch 8.2.0818: Vim9: using a discovery phase doesn't work well

Problem:    Vim9: using a discovery phase doesn't work well.
Solution:   Remove the discovery phase, instead compile a function only when
            it is used.  Add :defcompile to compile def functions earlier.
diff --git a/src/version.c b/src/version.c
index 94084c3..a5d2a8f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    818,
+/**/
     817,
 /**/
     816,