RFR: JDK-8289106: Add model of class file versions to core reflection [v6]

[Joe Darcy]

> JDK-8289106: Add model of class file versions to core reflection

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 18 additional commits since the last revision:

 - Implement code review feedback.
 - Update ClassFileVersionTest.java.
 - Merge branch 'master' into JDK-8289106
 - Appease jcheck.
 - Finish more precise versioned location support; udpate tests.
 - Partial implementation of version-depdendent locations() with tests.
 - Merge branch 'master' into JDK-8289106
 - Merge branch 'master' into JDK-8289106
 - Add method to map from major class file version.
 - Merge branch 'master' into JDK-8289106
 - ... and 8 more: https://git.openjdk.org/jdk/compare/aedfcb9d...2e6dfc8e

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9299/files
  - new: https://git.openjdk.org/jdk/pull/9299/files/34aa4f42..2e6dfc8e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9299&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9299&range=04-05

  Stats: 14248 lines in 687 files changed: 8784 ins; 3529 del; 1935 mod
  Patch: https://git.openjdk.org/jdk/pull/9299.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9299/head:pull/9299

PR: https://git.openjdk.org/jdk/pull/9299