RFR: 8229517: Support for optional asynchronous/buffered logging

[Xin Liu]

This patch provides a buffer to store asynchrounous messages and flush them to
underlying files periodically.

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Commit messages:
 - 8229517: Support for optional asynchronous/buffered logging
 - 8229517: Support for optional asynchronous/buffered logging
 - 8229517: Support for optional asynchronous/buffered logging
 - 8229517: Support for optional asynchronous/buffered logging

Changes: https://git.openjdk.java.net/jdk/pull/3135/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3135&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8229517
  Stats: 523 lines in 12 files changed: 508 ins; 5 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3135.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3135/head:pull/3135

PR: https://git.openjdk.java.net/jdk/pull/3135