RFR: 8339290: Optimize ClassFile Utf8EntryImpl#writeTo [v15]

[Shaojin Wen]

> Use fast path for ascii characters 1 to 127 to improve the performance of writing Utf8Entry to BufferWriter.

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

  countGreaterThanZero -> CountNonNegatives

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/20772/files
  - new: https://git.openjdk.org/jdk/pull/20772/files/72b99bd7..431f55b4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20772&range=14
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20772&range=13-14

  Stats: 175 lines in 6 files changed: 83 ins; 81 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/20772.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20772/head:pull/20772

PR: https://git.openjdk.org/jdk/pull/20772