RFR: 8371792: Refactor barrier loop tests out of TestIfMinMax [v3]

[Galder Zamarreño]

> Trivial cleanup to move tests out of a test class whose description does not match these tests

Galder Zamarreño has updated the pull request incrementally with one additional commit since the last revision:

  Refactored to compiler.gcbarriers package

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Changes:
  - all: https://git.openjdk.org/jdk/pull/28385/files
  - new: https://git.openjdk.org/jdk/pull/28385/files/bb287ba6..278d4bce

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28385&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28385&range=01-02

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/28385.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28385/head:pull/28385

PR: https://git.openjdk.org/jdk/pull/28385