RFR: 8274851: [PPC64] Port zgc to linux on ppc64le

[Niklas Radomski]

Port the Z garbage collector ([JDK-8209683](https://bugs.openjdk.java.net/browse/JDK-8209683)) to linux on ppc64le.

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Commit messages:
 - Port zgc to linux on ppc64le

Changes: https://git.openjdk.java.net/jdk/pull/5842/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5842&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8274851
  Stats: 1275 lines in 11 files changed: 1264 ins; 0 del; 11 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5842.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5842/head:pull/5842

PR: https://git.openjdk.java.net/jdk/pull/5842