RFR: 8281284 : Write JSlider accessibility test [v7]

[lawrence.andrews]

> This testcase covers both old and new api ( api added in jdk17  getAccessibleAction(), getAccessibleActionCount() , getAccessibleActionDescription )
> 
> @shurymury 
> @savoptik

lawrence.andrews has updated the pull request incrementally with one additional commit since the last revision:

  Removed AccessibleJSliderTest.java and add SliderDemo.java & SliderDemo.html

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7355/files
  - new: https://git.openjdk.java.net/jdk/pull/7355/files/fcc32f70..ba20c416

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7355&range=06
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7355&range=05-06

  Stats: 202 lines in 5 files changed: 107 ins; 95 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7355.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7355/head:pull/7355

PR: https://git.openjdk.java.net/jdk/pull/7355