RFR: JDK-8301050: Detect Xen Virtualization on Linux aarch64 [v2]

[Matthias Baesken]

> With https://bugs.openjdk.org/browse/JDK-8300266 KVM and VMWare virtualization detection has been added; this should be enhanced by Xen detection.
> However it seems that for Xen we should look at other file system locations compared to the other virtualizations.
> more /sys/hypervisor/type
> xen
> seems to be available there.

Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:

  Do not scan the product_name file twice

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12217/files
  - new: https://git.openjdk.org/jdk/pull/12217/files/b71a062b..3ef5c503

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12217&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12217&range=00-01

  Stats: 17 lines in 1 file changed: 8 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/12217.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12217/head:pull/12217

PR: https://git.openjdk.org/jdk/pull/12217