RFR: 8265123: Add static factory methods to com.sun.net.httpserver.Filter [v5]

[Julia Boes]

> Add two static factory methods to com.sun.net.httpserver.Filter that facilitate the creation of pre- and post-processing Filters: 
> 
> `public static Filter beforeResponse(String description, Consumer<HttpExchange> filterImpl) {}`
> `public static Filter afterResponse(String description, Consumer<HttpExchange> filterImpl) {}`

Julia Boes has updated the pull request incrementally with one additional commit since the last revision:

  some more spec updates and small test cleanup

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3468/files
  - new: https://git.openjdk.java.net/jdk/pull/3468/files/8751f654..0e76acd4

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3468&range=04
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3468&range=03-04

  Stats: 24 lines in 2 files changed: 1 ins; 2 del; 21 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3468.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3468/head:pull/3468

PR: https://git.openjdk.java.net/jdk/pull/3468