[lworld] RFR: 8327729: [lworld] Adjust UnsafeTest.java for JDK-8327729

[David Simms]

putObject -> putReference

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

Commit messages:
 - 8327729: [lworld] Adjust UnsafeTest.java for JDK-8327729

Changes: https://git.openjdk.org/valhalla/pull/1230/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1230&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8327729
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1230.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1230/head:pull/1230

PR: https://git.openjdk.org/valhalla/pull/1230