RFR: 8329850: [AIX] Allow loading of different members of same shared library archive [v2]

[Joachim Kern]

> With [JDK-8320890](https://bugs.openjdk.org/browse/JDK-8320890) we introduced the capability not to load shared libraries twice if the application wants to do that. Instead we just rise a ref counter. Unfortunately this also suppresses the loading of a second member of a shared library.
> This fix introduces an additionally stored hash value for each loaded member and only suppresses duplicate loading if the same member is loaded twice.
> If a shared library has no member a hash value of 0 is used to make the code orthogonal.

Joachim Kern has updated the pull request incrementally with one additional commit since the last revision:

  change from hash to allocated string

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Changes:
  - all: https://git.openjdk.org/jdk/pull/18676/files
  - new: https://git.openjdk.org/jdk/pull/18676/files/de6897e4..3ec79644

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18676&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18676&range=00-01

  Stats: 17 lines in 1 file changed: 6 ins; 3 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/18676.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18676/head:pull/18676

PR: https://git.openjdk.org/jdk/pull/18676