[8318446](https://github.com/openjdk/jdk/pull/16245) brings MergeStore. We need a JMH Benchmark to evaluate the performance of various batch operations and the effect of MergeStore.
------------- Commit messages: - code format - add `setIntRL` & `setIntRLU` - add comments - add comments - copyright - add MergeStore Benchmark Changes: https://git.openjdk.org/jdk/pull/19734/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19734&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8334342 Stats: 870 lines in 1 file changed: 870 ins; 0 del; 0 mod Patch: https://git.openjdk.org/jdk/pull/19734.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/19734/head:pull/19734 PR: https://git.openjdk.org/jdk/pull/19734