RFR: 8354969: Add strdup function for ResourceArea

[Anton Artemov]

Added a strdup() method, as requested by the bug reporter. The method is added to Arena, but also available in ResourceArea, as requested. A test for the method is provided. 

Testing: tiers 1-3 on multiple platforms.

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Commit messages:
 - 8354969: Added strdup function for Arena and ResourceArea

Changes: https://git.openjdk.org/jdk/pull/24998/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24998&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8354969
  Stats: 17 lines in 2 files changed: 17 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24998.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24998/head:pull/24998

PR: https://git.openjdk.org/jdk/pull/24998