RFR: JDK-8317635: Improve GetClassFields test to verify correctness of field order

[Alex Menkov]

All test cases in getclfld007 had 1 (or 0) field in test classes/interfaces.
The change adds several fields in one of the test classes to verify order of the returned fields (as described by GetClassFields spec).
Additionally added "printdump" argument to the test agent to make the test more verbose.

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Commit messages:
 - test fix

Changes: https://git.openjdk.org/jdk/pull/16131/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16131&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8317635
  Stats: 17 lines in 3 files changed: 8 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/16131.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16131/head:pull/16131

PR: https://git.openjdk.org/jdk/pull/16131