RFR: JDK-8287524: Improve checkboxes to select releases on deprecated API page

[Hannes Wallnöfer]

The original purpose of this issue was to fix the problems of elements on the deprecated API list that can't be deselected because their release is not included in the list of checkboxes at the top of the page. This is fixed here by adding a checkbox for all elements/releases not included in the list if necessary. 

While working on it I discovered a few corner cases that produce undesirable output for the deprecated list. This includes the case of a single release (where a checkbox doesn't make any sense) and the case of some or all releases not having any occurrences in the `since` element of deprecated elements (in which case the checkbox is useless as well). A more detailed description of these cases is available in the [JBS issue](https://bugs.openjdk.java.net/browse/JDK-8287524).

As examples for the output generated with this change I uploaded JDK API docs:

http://cr.openjdk.java.net/~hannesw/8287524/api.00/deprecated-list.html

To illustrate behaviour in corner cases mentioned above I also uploaded deprecated pages generated by the `TestNewAPIListWriter` test (which despite its name also tests the "extended" deprecated list).

http://cr.openjdk.java.net/~hannesw/8287524/test.00/TestNewApiList/out-multi/deprecated-list.html
http://cr.openjdk.java.net/~hannesw/8287524/test.00/TestNewApiList/out-none/deprecated-list.html
http://cr.openjdk.java.net/~hannesw/8287524/test.00/TestNewApiList/out-package/deprecated-list.html
http://cr.openjdk.java.net/~hannesw/8287524/test.00/TestNewApiList/out-single/deprecated-list.html

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

Commit messages:
 - JDK-8287524: Improve checkboxes to select releases on deprecated API page

Changes: https://git.openjdk.java.net/jdk/pull/8973/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8973&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8287524
  Stats: 138 lines in 9 files changed: 41 ins; 22 del; 75 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8973.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8973/head:pull/8973

PR: https://git.openjdk.java.net/jdk/pull/8973