RFR: 8312151: Deprecate for removal the -Xdebug option

[Jaikiran Pai]

Can I please get a review of this change which proposes to deprecate for removal the  `-Xdebug` option of the `java` command? This addresses https://bugs.openjdk.org/browse/JDK-8312151?

As noted in the JBS issue this option is currently a no-op and has been there only for backward compatible since even Java 8 days.

A CSR has been drafted for this change https://bugs.openjdk.org/browse/JDK-8312216

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Commit messages:
 - 8312151: Deprecate for removal the -Xdebug option

Changes: https://git.openjdk.org/jdk/pull/14918/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14918&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312151
  Stats: 35 lines in 22 files changed: 0 ins; 8 del; 27 mod
  Patch: https://git.openjdk.org/jdk/pull/14918.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14918/head:pull/14918

PR: https://git.openjdk.org/jdk/pull/14918