hg: jdk/client: 8251166: Add automated testcases for changes done in JDK-8214112

[pankaj.b.bansal at oracle.com]

Changeset: ed87317c507c
Author:    pbansal
Date:      2020-08-16 11:44 +0530
URL:       https://hg.openjdk.java.net/jdk/client/rev/ed87317c507c

8251166: Add automated testcases for changes done in JDK-8214112
Reviewed-by: serb

+ test/jdk/javax/swing/JFormattedTextField/TestSelectedTextBackgroundColor.java
+ test/jdk/javax/swing/JPasswordField/TestSelectedTextBackgroundColor.java
+ test/jdk/javax/swing/JSpinner/TestSelectedTextBackgroundColor.java