RFR: 8328874: Class::forName0 should validate the class name length early [v9]

[Guanqiang Han]

> Validate class name length immediately after GetStringUTFLength() in Class.forName0. This prevents potential issues caused by overly long class names before they reach later code that would reject them, throwing ClassNotFoundException early.

Guanqiang Han has updated the pull request incrementally with one additional commit since the last revision:

  Update Class.java
  
  Use ModifiedUtf.utfLen instead of static import for readability

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Changes:
  - all: https://git.openjdk.org/jdk/pull/26802/files
  - new: https://git.openjdk.org/jdk/pull/26802/files/a6b669eb..e7e23d89

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26802&range=08
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26802&range=07-08

  Stats: 3 lines in 1 file changed: 1 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26802.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26802/head:pull/26802

PR: https://git.openjdk.org/jdk/pull/26802