git: openjdk/jdk11u-dev: 8252194: Add automated test for fix done in JDK-8218469

[Aleksey Shipilev]

Changeset: 9fec49cf
Author:    Aleksey Shipilev <shade at openjdk.org>
Date:      2021-08-13 06:54:56 +0000
URL:       https://git.openjdk.java.net/jdk11u-dev/commit/9fec49cf74142dcc9260a2de3780f9c4394154c3

8252194: Add automated test for fix done in JDK-8218469

Backport-of: 1ae6b533fbba433e64868aa3b6846041e3a91136

+ test/jdk/javax/swing/JSlider/TestJSliderRendering.java