RFR: 8342380: Implement JEP draft: Warn about use of Memory-Access Methods in `sun.misc.Unsafe` [v2]

[Alan Bateman]

> Change default value of the command line option --sun-misc-unsafe-memory-access from "allow" to "warn".

Alan Bateman 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 five additional commits since the last revision:

 - Merge branch 'master' into JDK-8342380
 - Update test
 - Merge branch 'master' into JDK-8342380
 - Update usage/man page
 - Initial commit

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21762/files
  - new: https://git.openjdk.org/jdk/pull/21762/files/85264b80..a9f99896

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21762&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21762&range=00-01

  Stats: 225679 lines in 3239 files changed: 123548 ins; 77490 del; 24641 mod
  Patch: https://git.openjdk.org/jdk/pull/21762.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21762/head:pull/21762

PR: https://git.openjdk.org/jdk/pull/21762