8368799: [lworld] Heapwalking functions may report array classes several times

[alexmenkov]

The change adds test to verify heap walking API (FollowReferences and IterateOverReachableObjects) do not reports array classes several times

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Progress

• Change must not contain extraneous whitespace
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Issue

• JDK-8368799: [lworld] Heapwalking functions may report array classes several times (Enhancement - P4)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/valhalla.git pull/1852/head:pull/1852
$ git checkout pull/1852

Update a local copy of the PR:
$ git checkout pull/1852
$ git pull https://git.openjdk.org/valhalla.git pull/1852/head

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$ git pr checkout 1852

View PR using the GUI difftool:
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https://git.openjdk.org/valhalla/pull/1852.diff

[bridgekeeper]

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[openjdk]

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See the Progress checklist in the description for automated requirements.