RFR: 8339317: Optimize ClassFile writeBuffer [v3]

[Shaojin Wen]

> A small optimization, optimize the BufferWriter implementation and use of ClassFile, provide faster patchInt and skip

Shaojin Wen has updated the pull request incrementally with one additional commit since the last revision:

  Update src/java.base/share/classes/jdk/internal/classfile/impl/BufWriterImpl.java
  
  Co-authored-by: Claes Redestad <claes.redestad at oracle.com>

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20780/files
  - new: https://git.openjdk.org/jdk/pull/20780/files/3d6868f7..d7227a9c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20780&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20780&range=01-02

  Stats: 5 lines in 1 file changed: 0 ins; 3 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/20780.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20780/head:pull/20780

PR: https://git.openjdk.org/jdk/pull/20780