RFR: JDK-8257086: Clarify differences between {Float, Double}.equals and == [v3]

[Joe Darcy]

> Updates to the specifications of Double.{equals, compareTo} to explain more explicitly why the obvious wrappers around "==" and "<"/"==" are not sufficient for floating-point values.
> 
> Once the wording is worked out, I'll replicate it for the analogous methods on Float.

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 six additional commits since the last revision:

 - Merge branch 'master' into JDK-8257086
 - Update reworked wording from @smarks.
 - Merge branch 'master' into JDK-8257086
 - Merge branch 'master' into JDK-8257086
 - Fix whitespace
 - Initial work for JDK-8257086.

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1699/files
  - new: https://git.openjdk.java.net/jdk/pull/1699/files/308b387d..9d80e279

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1699&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1699&range=01-02

  Stats: 61247 lines in 1475 files changed: 22192 ins; 24174 del; 14881 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1699.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1699/head:pull/1699

PR: https://git.openjdk.java.net/jdk/pull/1699