[jdk11u-dev] RFR: 8284549: JFR: FieldTable leaks FieldInfoTable member

[Zhengyu Gu]

A clean and low risk backport to fix a memory leak in jfr leak profiler.

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Commit messages:
 - Backport 92f5e42696847de7e47e238412d2d541a11bccd7

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/1055/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=1055&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8284549
  Stats: 16 lines in 1 file changed: 10 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/1055.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/1055/head:pull/1055

PR: https://git.openjdk.java.net/jdk11u-dev/pull/1055