[lworld] RFR: 8331521: [lworld] dynamic proxy class does not strictly need preload attributes

[Mandy Chung]

This PR takes out the generation of preload attributes in dynamic proxy.

If a proxy interface references any value classes, the value classes are listed in the preload attribute of the interface class.  The classes that are referenced by the proxy interface have already been loaded before the proxy class.  Hence the proxy class can be generated with no preload attributes as it essentially has no effect.

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Commit messages:
 - 8331521: [lworld] dynamic proxy class does not strictly need preload attributes

Changes: https://git.openjdk.org/valhalla/pull/1092/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1092&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331521
  Stats: 62 lines in 1 file changed: 6 ins; 54 del; 2 mod
  Patch: https://git.openjdk.org/valhalla/pull/1092.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1092/head:pull/1092

PR: https://git.openjdk.org/valhalla/pull/1092