RFR: 7903532: JOL: Hotspot layouter assumes array bases are aligned to 4 bytes

[Aleksey Shipilev]

This is actually not true in current VMs, due to [JDK-8139457](https://bugs.openjdk.org/browse/JDK-8139457). This means HotspotLayouter underestimates the array sizes. This was not caught before, because we did not have good tests for arrays.

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Commit messages:
 - Fix

Changes: https://git.openjdk.org/jol/pull/49/files
 Webrev: https://webrevs.openjdk.org/?repo=jol&pr=49&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903532
  Stats: 145 lines in 9 files changed: 92 ins; 29 del; 24 mod
  Patch: https://git.openjdk.org/jol/pull/49.diff
  Fetch: git fetch https://git.openjdk.org/jol.git pull/49/head:pull/49

PR: https://git.openjdk.org/jol/pull/49