[master] RFR: 8310010: [Lilliput] SA: Fix oop array element alignment

[Roman Kennke]

When running with -COOPS, oop array elements need to be 8-byte-aligned. We have this correct in runtime, but not in the SA. Notably, the problem manifests with ZGC.
The problem is already fixed in #11044.

Testing:
 - [x] serviceability/sa -XX:-UseCompressedOops

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Commit messages:
 - 8310010: [Lilliput] SA: Fix oop array element alignment

Changes: https://git.openjdk.org/lilliput/pull/96/files
 Webrev: https://webrevs.openjdk.org/?repo=lilliput&pr=96&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310010
  Stats: 21 lines in 2 files changed: 12 ins; 7 del; 2 mod
  Patch: https://git.openjdk.org/lilliput/pull/96.diff
  Fetch: git fetch https://git.openjdk.org/lilliput.git pull/96/head:pull/96

PR: https://git.openjdk.org/lilliput/pull/96