patch 8.2.0279: Vim9: no test for deleted :def function

Problem:    Vim9: no test for deleted :def function.
Solution:   Add a test.  Clear uf_cleared flag when redefining a function.
diff --git a/src/version.c b/src/version.c
index d74b0fa..d748416 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    279,
+/**/
     278,
 /**/
     277,