RFR: 8298468: Clean up class_loader parameters

[Coleen Phillimore]

This patch passes ClassLoaderData* rather than Handle class_loader to the LoaderConstraintTable and to some functions in SystemDictionary that only need ClassLoaderData.  In general, class loading uses ClassLoaderData unless it has to call up to Java in loadClass().  There were a lot of unnecessary conversions back and forth.
Tested with tier1-4.

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Commit messages:
 - 8298468: Clean up class_loader parameters
 - 8298468: Clean up class_loader parameters

Changes: https://git.openjdk.org/jdk/pull/11672/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11672&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8298468
  Stats: 102 lines in 5 files changed: 10 ins; 26 del; 66 mod
  Patch: https://git.openjdk.org/jdk/pull/11672.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11672/head:pull/11672

PR: https://git.openjdk.org/jdk/pull/11672