[jdk21u-dev] RFR: 8313905: Checked_cast assert in CDS compare_by_loader

[Goetz Lindenmaier]

I backport this for parity with 21.0.7-oracle.

Resolved because "8313564: Fix -Wconversion warnings in classfile code" is not in 21.
Probably clean anyways.

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Commit messages:
 - Backport bd1b9427410c458215e9e89eeff6e4d30592a4a4

Changes: https://git.openjdk.org/jdk21u-dev/pull/1290/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1290&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8313905
  Stats: 6 lines in 2 files changed: 4 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1290.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1290/head:pull/1290

PR: https://git.openjdk.org/jdk21u-dev/pull/1290