RFR: 8358799: Refactor os::jvm_path()

[Calvin Cheung]

The linux, bsd, and aix versions of os::jvm_path() are very similar and can be combined into one in os_posix.cpp.

Passed tiers 1 - 3 tests.
However, tests were not run on the aix platform since it is not one of the Oracle supported platforms.

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Commit messages:
 - 8358799: Refactor os::jvm_path()

Changes: https://git.openjdk.org/jdk/pull/25675/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25675&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8358799
  Stats: 293 lines in 4 files changed: 82 ins; 211 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/25675.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25675/head:pull/25675

PR: https://git.openjdk.org/jdk/pull/25675