RFR: 8308748: JNU_GetStringPlatformChars may write to String's internal memory array

[Rudi Horn]

This change prevents the contents of the internal string array from being copied back when releasing it.

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Commit messages:
 - Use JNI_ABORT to release string bytes

Changes: https://git.openjdk.org/jdk/pull/14117/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14117&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8308748
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/14117.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14117/head:pull/14117

PR: https://git.openjdk.org/jdk/pull/14117