RFR: 7903903: JMH: Tighten up generated code density

Tue Dec 10 16:22:34 UTC 2024

Part of [JDK-8345302](https://bugs.openjdk.org/browse/JDK-8345302), we want to generate denser scaffolding code. This is an umbrella task to tighten up the generated code without heavy restructuring.

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Commit messages:
 - Optimize imports
 - Touchups
 - Shared init
 - Touchups

Changes: https://git.openjdk.org/jmh/pull/142/files
  Webrev: https://webrevs.openjdk.org/?repo=jmh&pr=142&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903903
  Stats: 48 lines in 3 files changed: 15 ins; 16 del; 17 mod
  Patch: https://git.openjdk.org/jmh/pull/142.diff
  Fetch: git fetch https://git.openjdk.org/jmh.git pull/142/head:pull/142

PR: https://git.openjdk.org/jmh/pull/142