Remove kasp Windows prereq check

Now that the timing issue is fixed, we can enable the kasp test
again on Windows.

(cherry picked from commit 87c05fa62f)

bin/tests/system/kasp/prereq.sh

@@ -1,19 +0,0 @@
-#!/bin/sh
-#
-# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
-#
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-#
-# See the COPYRIGHT file distributed with this work for additional
-# information regarding copyright ownership.
-
-SYSTEMTESTTOP=..
-. $SYSTEMTESTTOP/conf.sh
-
-if [ "$CYGWIN" ]; then
-        echo_i "KASP test disabled on Windows for now due to timing issues"
-        exit 255
-fi
-exit 0