[lworld] RFR: 8335254: [lworld] Test ObjectMethods.java doesn't test Object's default clone() method on values

[Frederic Parain]

Increase test coverage of cloneable values.

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Commit messages:
 - Extend test to cloneable values

Changes: https://git.openjdk.org/valhalla/pull/1148/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1148&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8335254
  Stats: 37 lines in 1 file changed: 35 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/valhalla/pull/1148.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1148/head:pull/1148

PR: https://git.openjdk.org/valhalla/pull/1148