RFR: JDK-8322648: Improve class initialization barrier in TemplateTable::_new for PPC

[Varada M]

ppc port implementation of https://github.com/openjdk/jdk/pull/17006

Fastdebug and Release : build and tier1 testing successful.

JBS Issue : [JDK-8322648](https://bugs.openjdk.org/browse/JDK-8322648)

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Commit messages:
 - JDK-8322648: Improve class initialization barrier in TemplateTable::_new for PPC
 - JDK-8322648: Improve class initialization barrier in TemplateTable::_new for PPC
 - JDK-8322648: Improve class initialization barrier in TemplateTable::_new for PPC

Changes: https://git.openjdk.org/jdk/pull/17518/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17518&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8322648
  Stats: 7 lines in 1 file changed: 3 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/17518.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17518/head:pull/17518

PR: https://git.openjdk.org/jdk/pull/17518