patch 8.2.4940: some code is never used

Problem:    Some code is never used.
Solution:   Remove dead code.  Add a few more test cases.
diff --git a/src/vim9compile.c b/src/vim9compile.c
index 8ab4e29..3eae14a 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -1140,7 +1140,7 @@
 	    break;
 	case dest_script:
 	    compile_load_scriptvar(cctx,
-		    name + (name[1] == ':' ? 2 : 0), NULL, NULL, TRUE);
+				  name + (name[1] == ':' ? 2 : 0), NULL, NULL);
 	    break;
 	case dest_env:
 	    // Include $ in the name here