RFR: 7903532: JOL: Hotspot layouter assumes array bases are aligned to 4 bytes [v3]

[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.

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Improve the failing test

-------------

Changes:
  - all: https://git.openjdk.org/jol/pull/49/files
  - new: https://git.openjdk.org/jol/pull/49/files/ae3887a8..df6794b3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jol&pr=49&range=02
 - incr: https://webrevs.openjdk.org/?repo=jol&pr=49&range=01-02

  Stats: 11 lines in 1 file changed: 6 ins; 2 del; 3 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