RFR: 8304292: Memory leak related to ClassLoader::update_class_path_entry_list [v4]

[Calvin Cheung]

> Please review this small fix for `ClassPathEntry` leak when there's a duplicate entry in the app class path (`-cp`) and the `check_for_duplicate` argument is set to `true`, the `ClassLoader::add_to_app_classpath_entries` function should delete the entry before returning. This fix also corrects the call to `update_class_path_entry_list` from `setup_app_search_path`; the `check_for_duplicate` argument should be set to `true`. Two test cases are included to exercise the code path.
> 
> Passed tiers 1 - 4 testing.

Calvin Cheung has updated the pull request incrementally with one additional commit since the last revision:

  fix minimal build failure

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15132/files
  - new: https://git.openjdk.org/jdk/pull/15132/files/86de8828..36921918

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15132&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15132&range=02-03

  Stats: 2 lines in 1 file changed: 1 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15132.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15132/head:pull/15132

PR: https://git.openjdk.org/jdk/pull/15132