[jdk21u-dev] RFR: 8320715: Improve the tests of test/hotspot/jtreg/compiler/intrinsics/float16

[Andrew Lu]

I backport this for parity with 21.0.3-oracle.

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Commit messages:
 - Backport 5dcf3a56cb425c3419273636729d2d83603be0d2

Changes: https://git.openjdk.org/jdk21u-dev/pull/577/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=577&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8320715
  Stats: 44 lines in 3 files changed: 28 ins; 0 del; 16 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/577.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/577/head:pull/577

PR: https://git.openjdk.org/jdk21u-dev/pull/577