git: openjdk/jdk-sandbox: datepicker-preview: SwingSet2 demo + Look and Feel change over fix

[duke]

Changeset: e9f8e127
Branch: datepicker-preview
Author:    Tejesh R <tejesh.r at oracle.com>
Date:      2025-12-16 12:34:14 +0000
URL:       https://git.openjdk.org/jdk-sandbox/commit/e9f8e127b5836e5eca81e366860a9d34001b8c12

SwingSet2 demo + Look and Feel change over fix

! make/CompileDemos.gmk
+ src/demo/share/jfc/SwingSet2/DatePickerDemo.java
! src/demo/share/jfc/SwingSet2/SwingSet2.java
+ src/demo/share/jfc/SwingSet2/resources/images/toolbar/JDatePicker.gif
! src/demo/share/jfc/SwingSet2/resources/swingset.properties
! src/demo/share/jfc/SwingSet2/resources/swingset_de.properties
! src/demo/share/jfc/SwingSet2/resources/swingset_ja.properties
! src/demo/share/jfc/SwingSet2/resources/swingset_zh_CN.properties
! src/java.desktop/share/classes/javax/swing/plaf/basic/BasicCalendarPanelUI.java
! src/java.desktop/share/classes/javax/swing/plaf/basic/BasicDatePickerUI.java