patch 9.0.0499: in :def function list created after const is locked

Problem:    In :def function list created after const is locked.
Solution:   Reset v_lock. (closes #11154)
diff --git a/src/testdir/test_vim9_assign.vim b/src/testdir/test_vim9_assign.vim
index 730212d..3957942 100644
--- a/src/testdir/test_vim9_assign.vim
+++ b/src/testdir/test_vim9_assign.vim
@@ -2023,6 +2023,13 @@
   unlet w:FLIST
 enddef
 
+def Test_create_list_after_const()
+  const a = 1
+  g:ll = []
+  assert_equal(0, islocked('g:ll'))
+  unlet g:ll
+enddef
+
 def Test_var_declaration_fails()
   var lines =<< trim END
     vim9script
diff --git a/src/version.c b/src/version.c
index 16ba3ee..415897a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    499,
+/**/
     498,
 /**/
     497,
diff --git a/src/vim9execute.c b/src/vim9execute.c
index 22dfaaa..c2a3310 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -200,6 +200,7 @@
     tv = STACK_TV_BOT(-1);
     tv->v_type = VAR_LIST;
     tv->vval.v_list = list;
+    tv->v_lock = 0;
     if (list != NULL)
 	++list->lv_refcount;
     return OK;