RFR: 8315750: Update subtype check profile collection on PPC following 8308869

[Martin Doerr]

Before this PR:

Benchmark                                         (typePollution)   Mode  Cnt   Score   Error   Units
RequireNonNullCheckcastScalability.isDuplicated1            false  thrpt   20  75,053 ± 0,197  ops/us
RequireNonNullCheckcastScalability.isDuplicated1             true  thrpt   20  42,983 ± 5,537  ops/us


With this PR:

Benchmark                                         (typePollution)   Mode  Cnt   Score   Error   Units
RequireNonNullCheckcastScalability.isDuplicated1            false  thrpt   20  80,815 ± 1,099  ops/us
RequireNonNullCheckcastScalability.isDuplicated1             true  thrpt   20  53,129 ± 0,107  ops/us

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Commit messages:
 - 8315750: Update subtype check profile collection on PPC following 8308869

Changes: https://git.openjdk.org/jdk/pull/15685/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15685&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315750
  Stats: 144 lines in 3 files changed: 27 ins; 89 del; 28 mod
  Patch: https://git.openjdk.org/jdk/pull/15685.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15685/head:pull/15685

PR: https://git.openjdk.org/jdk/pull/15685