RFR: 8120: Build JMC for Linux aarch64

[Marcus Hirt]

It was asked for at Adoptium, issue 46:
https://github.com/adoptium/jmc-build/issues/46

I don't have an M1 with Linux installed, so I have no way of verifying this, unfortunately. Perhaps someone out there can help.

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Commit messages:
 - 8120: Build JMC for Linux aarch64

Changes: https://git.openjdk.org/jmc/pull/514/files
 Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=514&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-8120
  Stats: 31 lines in 2 files changed: 29 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jmc/pull/514.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/514/head:pull/514

PR: https://git.openjdk.org/jmc/pull/514