RFR: 8344611: Add missing classpath exception

[Amit Kumar]

On Wed, 20 Nov 2024 10:46:54 GMT, Sorna Sarathi <duke at openjdk.org> wrote:

> This PR adds missing Classpath exception in several files.
> 
> JBS Issue: [JDK-8334611](https://bugs.openjdk.org/browse/JDK-8344611)

Do similar change for: 

src/java.base/share/native/libjava/ub.h
src/jdk.jlink/share/classes/jdk/tools/jlink/internal/runtimelink/JimageDiffGenerator.java
src/jdk.jlink/share/classes/jdk/tools/jlink/internal/runtimelink/ResourcePoolReader.java

Marked as reviewed by amitkumar (Committer).

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

Changes requested by amitkumar (Committer).

PR Review: https://git.openjdk.org/jdk/pull/22272#pullrequestreview-2448712572
PR Review: https://git.openjdk.org/jdk/pull/22272#pullrequestreview-2448863289