RFR: 8275449: Add linux-aarch64-zero build profile

[Mikhailo Seledtsov]

Please review this small change that adds the linux-aarch64 zero build profile.

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Commit messages:
 - Add linux-aarch64-zero to jib build profiles
 - Add aarch64 as target CPU for libffi lookup

Changes: https://git.openjdk.java.net/jdk/pull/6024/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6024&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8275449
  Stats: 12 lines in 2 files changed: 11 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6024.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6024/head:pull/6024

PR: https://git.openjdk.java.net/jdk/pull/6024