patch 8.2.1437: Vim9: 'statusline' is evaluated using Vim9 script syntax

Problem:    Vim9: 'statusline' is evaluated using Vim9 script syntax.
Solution:   Always use legacy script syntax.
diff --git a/src/eval.c b/src/eval.c
index 07b30c7..984835b 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -520,6 +520,7 @@
 /*
  * Call eval_to_string() without using current local variables and using
  * textwinlock.  When "use_sandbox" is TRUE use the sandbox.
+ * Use legacy Vim script syntax.
  */
     char_u *
 eval_to_string_safe(
@@ -528,7 +529,9 @@
 {
     char_u	*retval;
     funccal_entry_T funccal_entry;
+    int		save_sc_version = current_sctx.sc_version;
 
+    current_sctx.sc_version = 1;
     save_funccal(&funccal_entry);
     if (use_sandbox)
 	++sandbox;
@@ -538,6 +541,7 @@
 	--sandbox;
     --textwinlock;
     restore_funccal();
+    current_sctx.sc_version = save_sc_version;
     return retval;
 }