RFR: 8295951: intermittent cmp_baseline task failures with CDS files

[Calvin Cheung]

The cmp_baseline build target fails intermittently due to the `java/util/concurrent/atomic/Striped64$Cell` class is loaded sometimes when running the `HelloClasslist.java` app.
To avoid this problem, always load the `Striped64$Cell`class from the `HelloClasslist.java` app so that the generated classlist and CDS archive would be the same as the baseline build.

Ran the <platform>-cmp-baseline build target repeatedly on Oracle supported platforms.

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Commit messages:
 - 8295951: intermittent cmp_baseline task failures with CDS files

Changes: https://git.openjdk.org/jdk/pull/12272/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12272&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295951
  Stats: 7 lines in 1 file changed: 6 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/12272.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12272/head:pull/12272

PR: https://git.openjdk.org/jdk/pull/12272