[jdk11u-dev] RFR: 8274056: JavaAccessibilityUtilities leaks JNI objects

[Martin Doerr]

Clean backport of JDK-8274056.

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Commit messages:
 - Backport 42d5d2abaad8a88a5e1326ea8b4494aeb8b5748b

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/437/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=437&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8274056
  Stats: 8 lines in 1 file changed: 5 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/437.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/437/head:pull/437

PR: https://git.openjdk.java.net/jdk11u-dev/pull/437