RFR: 8306678: Replace use of os.version with an internal Version record [v3]

[Roger Riggs]

> Create an internal Version record to hold and compare versions of the form (major, minor, micro).
> Add `OperatingSystem.version()` to return the version of the running OS.
> Replace uses of os.version in java.base.
> Subsequent PRs will apply to uses in other modules including, jdk.jlink, jdk.jpackage, and java.desktop.

Roger Riggs has updated the pull request incrementally with one additional commit since the last revision:

  Simplify initialization in ClassLoaderHelper and fix VersionTest.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13584/files
  - new: https://git.openjdk.org/jdk/pull/13584/files/01bc9cbf..8e3d9df3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13584&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13584&range=01-02

  Stats: 9 lines in 2 files changed: 0 ins; 3 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/13584.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13584/head:pull/13584

PR: https://git.openjdk.org/jdk/pull/13584