RFR: 8339320: Optimize ClassFile Utf8EntryImpl#inflate

[Shaojin Wen]

A very small optimization, split the large method inflate, split the infrequently used paths into a method inflateCHAR

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Commit messages:
 - Update src/java.base/share/classes/jdk/internal/classfile/impl/AbstractPoolEntry.java
 - Update src/java.base/share/classes/jdk/internal/classfile/impl/AbstractPoolEntry.java
 - Suggestions from @liach
 - fix build error
 - optimize Utf8EntryImpl inflate

Changes: https://git.openjdk.org/jdk/pull/20767/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20767&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339320
  Stats: 75 lines in 1 file changed: 22 ins; 20 del; 33 mod
  Patch: https://git.openjdk.org/jdk/pull/20767.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20767/head:pull/20767

PR: https://git.openjdk.org/jdk/pull/20767