RFR: JDK-8320005 : Allow loading of shared objects with .a extension on AIX [v8]

[Suchismith Roy]

> J2SE agent does not start and throws error when it tries to find the shared library ibm_16_am.
> After searching for ibm_16_am.so ,the jvm agent throws and error as dll_load fails.It fails to identify the shared library ibm_16_am.a shared archive file on AIX.
> Hence we are providing a function which will additionally search for .a file on AIX ,when the search for .so file fails.

Suchismith Roy has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 24 commits:

 - Fix merge conflicts
 - Spaces fix
 - Restore lines
 -  Remove trailing spaces.
 - Change return type
 - Change dll load function signature that does dlopen
 - Remove AIX macros
 - Add wrapper function to check extension before dlopen
 - merge pr/16920
 - cosmetic changes
 - ... and 14 more: https://git.openjdk.org/jdk/compare/36f4b34f...6a5ce4a2

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Changes: https://git.openjdk.org/jdk/pull/16604/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16604&range=07
  Stats: 28 lines in 2 files changed: 27 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/16604.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16604/head:pull/16604

PR: https://git.openjdk.org/jdk/pull/16604