RFR: 8343770: Build fails due to use of sun.misc.Unsafe in LoopOverRandom

[Maurizio Cimadamore]

This small PR fixes a build failure due to usage of sun.misc.Unsafe in a new benchmark.

FFM benchmarks appear to be broken -- because of JDK-8332744 -- but we will fix that separately.

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

Commit messages:
 - Initial push

Changes: https://git.openjdk.org/jdk/pull/21958/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21958&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343770
  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/21958.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21958/head:pull/21958

PR: https://git.openjdk.org/jdk/pull/21958