RFR: JDK-8303071: Memory leaks in libjdwp

[Justin King]

Fix minor memory leaks in libjdwp.

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Commit messages:
 - Memory leaks in libjdwp

Changes: https://git.openjdk.org/jdk/pull/12716/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12716&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8303071
  Stats: 6 lines in 2 files changed: 5 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/12716.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12716/head:pull/12716

PR: https://git.openjdk.org/jdk/pull/12716