Add two static factory methods to com.sun.net.httpserver 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) {}`
-------------
Commit messages:
- update specs and expand test
- initial commit
- (drive-by) add detail msg for AssertionError
Changes: https://git.openjdk.java.net/jdk/pull/3468/files
Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3468&range=00
Issue: https://bugs.openjdk.java.net/browse/JDK-8265123
Stats: 282 lines in 3 files changed: 279 ins; 0 del; 3 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
