RFR: 8334734: Remove specialized readXxxEntry methods from ClassReader

[Chen Liang]

`ClassReader.readXxxEntry` were added before we had generic, type-aware `readEntry` and `readEntryOrNull` APIs (#19330). We should remove these specialized versions in favor of the generic version to reduce API bloating.

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Commit messages:
 - Copyright years
 - 8334734: Remove specialized readXxxEntry methods from ClassReader

Changes: https://git.openjdk.org/jdk/pull/19833/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19833&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8334734
  Stats: 169 lines in 9 files changed: 1 ins; 111 del; 57 mod
  Patch: https://git.openjdk.org/jdk/pull/19833.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19833/head:pull/19833

PR: https://git.openjdk.org/jdk/pull/19833