[jdk11u-dev] RFR: 8252114: Windows-AArch64: Enable and test ZGC and ShenandoahGC

[Reka Kovacs]

The original commit and the backport don't have a lot to do with each other quite honestly, but they both fit under the JBS issue. The original commit enabled ZGC for Windows/AArch64 (Shenandoah was already enabled on all AArch64 platforms), while this one enables Shenandoah.

This is part of the Windows/AArch64 port.

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Depends on: https://git.openjdk.java.net/jdk11u-dev/pull/301

Commit messages:
 - Backport 96f722cf63ae0e115612d816aa339d38074d3ade

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/304/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=304&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8252114
  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/304.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/304/head:pull/304

PR: https://git.openjdk.java.net/jdk11u-dev/pull/304