RFR: 8304818: Prune HttpURLConnection cache when corresponding Authenticator is garbage collected [v11]

[Michael McMahon]

> Hi,
> 
> Can I get a review for this please? This change uses a Cleaner to check when java.net.Authenticator instances become unreachable, and then prunes the authentication cache for entries that correspond to that Authenticator and therefore cannot be used again. This stops the authentication cache from growing in size unbounded. Note, this only happens in the probably unusual case where more than one Authenticator object is used. Normally there is no reason to use more than one instance.
> 
> Thanks,
> Michael.

Michael McMahon 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 14 additional commits since the last revision:

 - Merge branch 'master' into auth
 - Update src/java.base/share/classes/sun/net/www/protocol/http/AuthCacheImpl.java
   
   Co-authored-by: Daniel Fuchs <67001856+dfuch at users.noreply.github.com>
 - error in test
 - Jai's review
 - update to remove dependency on AuthCacheImpl in j.n.Authenticator
 - Merge branch 'master' into auth
 - removed AuthenticationInfo serialization code plus other updates
 - update
 - Merge branch 'master' into auth
 - updated implementation and reimpl of AuthenticatoKeys
 - ... and 4 more: https://git.openjdk.org/jdk/compare/88b42e2a...d2d27f8c

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13159/files
  - new: https://git.openjdk.org/jdk/pull/13159/files/03d9b9ac..d2d27f8c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13159&range=10
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13159&range=09-10

  Stats: 5049 lines in 173 files changed: 2316 ins; 1326 del; 1407 mod
  Patch: https://git.openjdk.org/jdk/pull/13159.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13159/head:pull/13159

PR: https://git.openjdk.org/jdk/pull/13159