RFR: JDK-8303181: Memory leak in ClassLoaderExt::setup_app_search_path [v2]

[Justin King]

> Fix memory leak by removing unnecessary `os::strdup` call. The string is passed as a const pointer to all functions.

Justin King 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 three additional commits since the last revision:

 - Switch to strdup_check_oom with free
   
   Signed-off-by: Justin King <jcking at google.com>
 - Merge remote-tracking branch 'upstream/master' into classloaderext-leak
 - Remove unnecessary strdup
   
   Signed-off-by: Justin King <jcking at google.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12748/files
  - new: https://git.openjdk.org/jdk/pull/12748/files/d440b68f..78f04fa7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12748&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12748&range=00-01

  Stats: 5499 lines in 272 files changed: 3377 ins; 1053 del; 1069 mod
  Patch: https://git.openjdk.org/jdk/pull/12748.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12748/head:pull/12748

PR: https://git.openjdk.org/jdk/pull/12748