RFR: 8326949: Authorization header is removed when a proxy Authenticator is set on HttpClient [v4]

[Michael McMahon]

> This fix relaxes the constraints on user set authentication headers. Currently, any user set authentication headers are filtered out, if the HttpClient has an Authenticator set. The reason being that the authenticator is expected to manage authentication.  With this fix, it will be possible to use pre-emptive authentication through user set headers, even if an authenticator is set. The expected use case is where the authenticator would manage either proxy or server authentication and the user set headers would manage server authentication if the authenticator is managing proxy (or vice versa).
> If the pre-emptive authentication fails, then this behavior is disabled on further retries and it would be up to the authenticator to provide the right credentials then.
> 
> 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 102 additional commits since the last revision:

 - Merge branch 'master' into 8326949-authorize
 - 8336843: Deprecate java.util.zip.ZipError for removal
   
   Reviewed-by: liach, lancea
 - 8341597: ZipFileInflaterInputStream input buffer size uses uncompressed size
   
   Reviewed-by: lancea
 - 8339220: [s390x] TestIfMinMax.java failure
   
   Reviewed-by: lucy, aph
 - 8341594: Use Unsafe to coalesce reads in java.util.zip.ZipUtils
   
   Reviewed-by: lancea
 - 8339836: Open source several AWT Mouse tests - Batch 1
   
   Reviewed-by: honkar, prr
 - 8339982: Open source several AWT Mouse tests - Batch 2
   
   Reviewed-by: psadhukhan
 - 8341668: Shenandoah: assert(tail_bits < (idx_t)BitsPerWord) failed: precondition
   
   Reviewed-by: ysr
 - 8341581: Optimize BytecodeHelpers validate slot
   
   Reviewed-by: liach
 - 8341278: Open source few TrayIcon tests - Set7
   
   Reviewed-by: azvegint
 - ... and 92 more: https://git.openjdk.org/jdk/compare/ea3b6fde...99553407

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21249/files
  - new: https://git.openjdk.org/jdk/pull/21249/files/68dde1ee..99553407

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21249&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21249&range=02-03

  Stats: 25379 lines in 383 files changed: 21588 ins; 2377 del; 1414 mod
  Patch: https://git.openjdk.org/jdk/pull/21249.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21249/head:pull/21249

PR: https://git.openjdk.org/jdk/pull/21249