patch 8.2.5018: Vim9: some code is not covered by tests

Problem:    Vim9: some code is not covered by tests.
Solution:   Delete dead code.
diff --git a/src/vim9expr.c b/src/vim9expr.c
index a52f2c7..b2bb405 100644
--- a/src/vim9expr.c
+++ b/src/vim9expr.c
@@ -442,7 +442,7 @@
 
 	    switch (**arg)
 	    {
-		case 'v': res = generate_LOADV(cctx, name, error);
+		case 'v': res = generate_LOADV(cctx, name);
 			  break;
 		case 's': if (current_script_is_vim9())
 			  {