RFR: 8041: JfrRulesReport -format json produce incomplete results

[Suchita Chaturvedi]

The output of JSON report contains blank placeholders like below:
"message": "",
"detailedMessage": ""

After the fix:

"message": "No long socket write pauses were found in this recording (the longest was 26.678 ms).",
 "detailedMessage": "Note that there are some socket write patterns with high duration writes that we consider to be normal and are therefore excluded. Such patterns include JMX RMI communication."

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Commit messages:
 - 8041: JfrRulesReport -format json produce incomplete results

Changes: https://git.openjdk.org/jmc/pull/468/files
 Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=468&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-8041
  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jmc/pull/468.diff
  Fetch: git fetch https://git.openjdk.org/jmc pull/468/head:pull/468

PR: https://git.openjdk.org/jmc/pull/468