[code-reflection] RFR: Onnx Record to tuple types conversion moved to TypeConverter

[Adam Sotona]

+ detection of constant arrays
- removal of ArrayLen annotation

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Commit messages:
 - imports cleanup
 - Record to tuple types conversion moved to TypeConverter

Changes: https://git.openjdk.org/babylon/pull/477/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=477&range=00
  Stats: 506 lines in 5 files changed: 290 ins; 170 del; 46 mod
  Patch: https://git.openjdk.org/babylon/pull/477.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/477/head:pull/477

PR: https://git.openjdk.org/babylon/pull/477