RFR: JDK-8285497: Add system property for Java SE specification maintenance version [v7]

[Joe Darcy]

> Add a new system property, java.specification.maintenance.version, to return the maintenance release number of the Java SE specification being implemented. The property is unset, optional in the terminology of System.getProperties, for an initial release of a specification.
> 
> Please also review the CSR https://bugs.openjdk.java.net/browse/JDK-8285764
> 
> I'll update copyright years before an integration.

Joe Darcy 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 12 additional commits since the last revision:

 - Respond to mbreinhold review feedback.
 - Merge branch 'master' into JDK-8285497
 - Update wording to address review feedback.
 - Merge branch 'master' into JDK-8285497
 - Change punctuation from review feedback.
 - Respond to review feedback; make sequence of values explicit.
 - Respond to review feedback.
 - Respond to review feedback.
 - Respond to CSR feedback.
 - Merge branch 'master' into JDK-8285497
 - ... and 2 more: https://git.openjdk.java.net/jdk/compare/f4e6f016...7b7720cf

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8437/files
  - new: https://git.openjdk.java.net/jdk/pull/8437/files/741ececa..7b7720cf

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8437&range=06
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8437&range=05-06

  Stats: 7420 lines in 158 files changed: 4834 ins; 1036 del; 1550 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8437.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8437/head:pull/8437

PR: https://git.openjdk.java.net/jdk/pull/8437