RFR: 8252114: Windows-AArch64: Enable and test ZGC and ShenandoahGC

[Monica Beckwith]

ZGC and ShenandoahGC are two low latency GCs in OpenJDK HotSpot. We will enable and run microbenchmarks and scaling
tests for both. After enabling, I ran JTRegs, a few micros, and SPECJBB2015 (heap and multi-JVM) scaling tests for both
the GCs.

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Commit messages:
 - JDK-8252114: Windows-AArch64: Enable and test ZGC and ShenandoahGC

Changes: https://git.openjdk.java.net/jdk/pull/97/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=97&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8252114
  Stats: 8 lines in 1 file changed: 6 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/97.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/97/head:pull/97

PR: https://git.openjdk.java.net/jdk/pull/97