RFR: 8353274: [PPC64] Bug related to -XX:+UseCompactObjectHeaders -XX:-UseSIGTRAP in JDK-8305895

[Martin Doerr]

`MacroAssembler::ic_check` compares the `Klass*` in the compact format (no decode). However, a right shift is needed in case of `UseCompactObjectHeaders` (see `load_narrow_klass_compact`). This was missing in the slower version which doesn't use SIGTRAP.

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Commit messages:
 - 8353274: [PPC64] Bug related to -XX:+UseCompactObjectHeaders -XX:-UseSIGTRAP in JDK-8305895

Changes: https://git.openjdk.org/jdk/pull/24331/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24331&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8353274
  Stats: 23 lines in 2 files changed: 8 ins; 12 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/24331.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24331/head:pull/24331

PR: https://git.openjdk.org/jdk/pull/24331