RFR: 8304059: Use InstanceKlass in dependencies

[Coleen Phillimore]

Please review this small change to eliminate InstanceKlass::cast() calls for things that should be already InstanceKlass.
Tested with tier1-4.

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Commit messages:
 - 8304059: Use InstanceKlass in dependencies

Changes: https://git.openjdk.org/jdk/pull/13005/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13005&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304059
  Stats: 27 lines in 4 files changed: 0 ins; 1 del; 26 mod
  Patch: https://git.openjdk.org/jdk/pull/13005.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/13005/head:pull/13005

PR: https://git.openjdk.org/jdk/pull/13005