[jdk11u-dev] RFR: 7124293: [macosx] VoiceOver reads percentages rather than the actual values for sliders.

[Martin Doerr]

Clean backport of [JDK-7124293](https://bugs.openjdk.java.net/browse/JDK-7124293)

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Commit messages:
 - Backport 6168452b9fe2b818cfe52a3807d90bcc849e068a

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/1098/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=1098&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-7124293
  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/1098.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/1098/head:pull/1098

PR: https://git.openjdk.java.net/jdk11u-dev/pull/1098