patch 8.2.4215: illegal memory access when copying lines in Visual mode

Problem:    Illegal memory access when copying lines in Visual mode.
Solution:   Adjust the Visual position after copying lines.

src/ex_cmds.c

@@ -866,6 +866,8 @@ ex_copy(linenr_T line1, linenr_T line2, linenr_T n)
     }
 
     appended_lines_mark(n, count);
+    if (VIsual_active)
+	check_pos(curbuf, &VIsual);
 
     msgmore((long)count);
 }