This PR makes sure that `MemorySegment` is initialized *before* any of its subclasses. This is done by centralizing all the memory segment factories in a single implementation class (`SegmentFactories`). Doing so addresses a possible deadlock condition when using multiple threads.
------------- Commit messages: - Add test - Add copyright - Initial push Changes: https://git.openjdk.org/jdk/pull/16187/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16187&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8317514 Stats: 484 lines in 12 files changed: 313 ins; 147 del; 24 mod Patch: https://git.openjdk.org/jdk/pull/16187.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/16187/head:pull/16187 PR: https://git.openjdk.org/jdk/pull/16187
