RFR: JDK-8276447 Deprecate finalization-related methods for removal

[Brent Christian]

Here are the code changes for the "Deprecate finalizers in the standard Java API" portion of JEP 421 ("Deprecate Finalization for Removal") for code review.

This change makes the indicated deprecations, and updates the API spec for JEP 421. It also updates the relevant @SuppressWarning annotations.

The CSR has been approved.
An automated test build+test run passes cleanly (FWIW :D ).

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Commit messages:
 - merge
 - @SuppressWarnings(removal) in Windows CKey.java
 - Add jls tag to runFinalization methods
 - Update wording of Object.finalize, new paragraph is now bold
 - update Object.finalize javadoc
 - update Object.finalize JavaDoc and @deprecated tag
 - Update Object.finalize deprecation message
 - Indicate that runFinalizers does nothing if finalization is disabled or removed
 - Fix @since on @Deprecated for java.lang.Enum
 - Clarify conditions for removal of Object.finalize method
 - ... and 21 more: https://git.openjdk.java.net/jdk/compare/89b125f4...eca95cb2

Changes: https://git.openjdk.java.net/jdk/pull/6465/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6465&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8276447
  Stats: 194 lines in 62 files changed: 54 ins; 38 del; 102 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6465.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6465/head:pull/6465

PR: https://git.openjdk.java.net/jdk/pull/6465