ops.c: eliminate static variable y_current

This variable isn't stateful, and should be passed around instead.

Helped-By: Scott Prager <splinterofchaos@gmail.com>
Helped-By: Michael Reed <m.reed@mykolab.com>

src/nvim/normal.c

@@ -1541,7 +1541,7 @@ void do_pending_operator(cmdarg_T *cap, int old_col, bool gui_yank)
           CancelRedo();
         }
       } else
-        (void)op_yank(oap, false, !gui_yank);
+        (void)op_yank(oap, !gui_yank);
       check_cursor_col();
       break;