patch 8.2.3209: Vim9: lambda doesn't find block-local variable

Problem:    Vim9: lambda doesn't find block-local variable.
Solution:   Adjust how a script-local variable is found. (closes #8614)
diff --git a/src/vim9compile.c b/src/vim9compile.c
index 06098d8..5ec3b3d 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -339,6 +339,7 @@
     hashitem_T	    *hi;
     int		    cc;
     sallvar_T	    *sav;
+    sallvar_T	    *found_sav;
     ufunc_T	    *ufunc;
 
     // Find the list of all script variables with the right name.
@@ -361,6 +362,7 @@
     // Go over the variables with this name and find one that was visible
     // from the function.
     ufunc = cctx->ctx_ufunc;
+    found_sav = sav;
     while (sav != NULL)
     {
 	int idx;
@@ -373,7 +375,8 @@
 	sav = sav->sav_next;
     }
 
-    return NULL;
+    // Not found, assume variable at script level was visible.
+    return found_sav;
 }
 
 /*