[jdk21u-dev] RFR: 8325659: Normalize Random usage by incubator vector tests

[Goetz Lindenmaier]

I backport this for parity with 21.0.7-oracle

I had to resolve because 21 has @enablePreview in the context.

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Commit messages:
 - Backport 4bba445d835837db5ab145edb24030fc6f42ec24

Changes: https://git.openjdk.org/jdk21u-dev/pull/1309/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1309&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8325659
  Stats: 469 lines in 69 files changed: 188 ins; 0 del; 281 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1309.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1309/head:pull/1309

PR: https://git.openjdk.org/jdk21u-dev/pull/1309