RFR: 8365483: Test sun/rmi/runtime/Log/6409194/NoConsoleOutput.java sometimes fails [v4]

[David Beaumont]

> The writer field of the handler needs to be re-checked for null inside the locked region before use.

David Beaumont has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Merge branch 'master' into jdk_8365483/squashed
 - License fix.
 - Adding test (thanks Jai)
 - Re-check writer after locking

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27173/files
  - new: https://git.openjdk.org/jdk/pull/27173/files/213361cb..d174f56d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27173&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27173&range=02-03

  Stats: 51969 lines in 1862 files changed: 31292 ins; 12627 del; 8050 mod
  Patch: https://git.openjdk.org/jdk/pull/27173.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27173/head:pull/27173

PR: https://git.openjdk.org/jdk/pull/27173