RFR: 8323183: ClassFile API performance improvements

[Adam Sotona]

ClassFile API performance related improvements have been separated from #17121 into this PR.

These improvements are important to minimize performance regression of
8294961: Convert java.base/java.lang.reflect.ProxyGenerator to use the Classfile API to generate proxy classes #17121

Please review.

Thanks,
Adam

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Commit messages:
 - Revert "8294961: Convert java.base/java.lang.reflect.ProxyGenerator to use the Classfile API to generate proxy classes"
 - Revert "performance improvements"
 - Revert "performance improvements"
 - Revert "performance improvements"
 - StackCounter fix
 - Update src/java.base/share/classes/jdk/internal/classfile/impl/StackCounter.java
 - minor StackCounter fix
 - applied the recommended changes
 - performance improvements
 - SplitConstantPool performance fix
 - ... and 4 more: https://git.openjdk.org/jdk/compare/2611a49e...bb2cf21c

Changes: https://git.openjdk.org/jdk/pull/17306/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17306&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8323183
  Stats: 92 lines in 2 files changed: 57 ins; 14 del; 21 mod
  Patch: https://git.openjdk.org/jdk/pull/17306.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17306/head:pull/17306

PR: https://git.openjdk.org/jdk/pull/17306