patch 9.1.1099: Vim9: import with extends may crash

Problem:  Vim9: import with extends may crash, v9.1.1087 wasn't the
          correct way to fix it)
Solution: When using an import class, Check for a valid class member
          variable at compile time (Yegappan Lakshmanan)

related: #16601
closes: #16603

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/vim9execute.c b/src/vim9execute.c
index 5022000..c7f0e67 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -2461,14 +2461,8 @@
 		otv = class->class_members_tv;
 	    }
 
-	    if (otv != NULL)
-	    {
-		clear_tv(&otv[lidx]);
-		otv[lidx] = *tv;
-	    }
-	    else
-		status = FAIL;
-
+	    clear_tv(&otv[lidx]);
+	    otv[lidx] = *tv;
 	}
 	else
 	{