RFR: 8298202: [AIX] Dead code elimination removed jfr constructor used by AIX

[Tyler Steele]

A very simple change to restore the 5 argument SystemProcess constructor used by JFR on AIX which is currently blocking the AIX build.

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Commit messages:
 - Restore 5 arg constructor for SystemProcess

Changes: https://git.openjdk.org/jdk/pull/11546/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11546&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8298202
  Stats: 8 lines in 1 file changed: 8 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/11546.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11546/head:pull/11546

PR: https://git.openjdk.org/jdk/pull/11546