[code-reflection] RFR: Onnx direct reflection over records as tuples

[Adam Sotona]

This PR removes `ExplicitOnnxOps.LoopReturn` and reflects directly on Records.

Unfortunately in some situations `new LoopReturn` cause javac crashing with IOOBE  at `jdk.incubator.code/jdk.incubator.code.internal.ReflectMethods$BodyScanner.thisValue(ReflectMethods.java:689)`.

Problematic use cases are at `WalkTheMazeTest::turnRight` and `WalkTheMazeTest::turnLeftWhileWall`.
While seamlessly working use cases are at `WalkTheMazeTest::walkAroundTheMaze` and `SimpleTest::forLoopAdd`.

As a temporary workaround any static factory method returning a record is also treated as a tuple constructor.

Please review.

Thanks,
Adam

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Commit messages:
 - Direct reflection over records as tuples

Changes: https://git.openjdk.org/babylon/pull/375/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=375&range=00
  Stats: 214 lines in 6 files changed: 58 ins; 132 del; 24 mod
  Patch: https://git.openjdk.org/babylon/pull/375.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/375/head:pull/375

PR: https://git.openjdk.org/babylon/pull/375