[code-reflection] RFR: Onnx direct reflection over records as tuples [v6]

[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

Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:

  main loop in WalkTheMazeTest use tuple with three tensors

-------------

Changes:
  - all: https://git.openjdk.org/babylon/pull/375/files
  - new: https://git.openjdk.org/babylon/pull/375/files/21fd970a..a4e9c5dc

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=375&range=05
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=375&range=04-05

  Stats: 35 lines in 1 file changed: 4 ins; 21 del; 10 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