RFR: 8317678: Fix up hashCode() for ZipFile.Source.Key [v5]

[Sean Coffey]

> Fix up java.util.zip.ZipFile$Source hashCode() impl so that duplicate Source objects aren't created for the same zip file.

Sean Coffey 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 six additional commits since the last revision:

 - update pae exception handling, correct test case typo and improve comments
 - Merge branch 'master' into 8317678-Zip-Source
 - minor test edits and comment updates
 - insert back lastmodified check. enhance testcase. more review comments
 - incorporate review comments
 - Initial changes

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/16115/files
  - new: https://git.openjdk.org/jdk/pull/16115/files/519014c7..7f9d3a90

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16115&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16115&range=03-04

  Stats: 9230 lines in 427 files changed: 4465 ins; 2942 del; 1823 mod
  Patch: https://git.openjdk.org/jdk/pull/16115.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16115/head:pull/16115

PR: https://git.openjdk.org/jdk/pull/16115