RFR: 8339939: [JVMCI] Don't compress abstract and interface Klasses

[Yudi Zheng]

https://github.com/openjdk/jdk/pull/19157 disallows storing abstract and interface Klasses in class metaspace. JVMCI has to respect this and avoids compressing abstract and interface Klasses

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Commit messages:
 - trim trailing whitespace
 - make JVMCI aware that some klass pointers are not compressible

Changes: https://git.openjdk.org/jdk/pull/20949/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20949&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339939
  Stats: 63 lines in 7 files changed: 56 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/20949.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20949/head:pull/20949

PR: https://git.openjdk.org/jdk/pull/20949