RFR: 8328880: Events::log_exception should limit the size of the logging message

[David Holmes]

This simple enhancement allows for `Exceptions::_throw` to limit the message length printed by `Events::log_exception` in the same way that unified logging is limited. We simply allow a `message_length_limit` variable to be passed down - default value zero which means no limit (i.e. the full `strlen` of the message will be printed).

Testing:
- tiers 1-3

Thanks

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Commit messages:
 - Fix whitespace
 - 8328880: Events::log_exception should limit the size of the logging message

Changes: https://git.openjdk.org/jdk/pull/20638/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20638&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8328880
  Stats: 18 lines in 3 files changed: 10 ins; 1 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/20638.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20638/head:pull/20638

PR: https://git.openjdk.org/jdk/pull/20638