[code-reflection] RFR: ONNX FFM Runtime initial work

[Adam Sotona]

This is initial work on ONNX FFM runtime with very raw connection with OnnxInterpreter and Tensor.

It is a rebase of https://github.com/PaulSandoz/babylon/pull/1

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Commit messages:
 - minor OnnxProtoBuilder change
 - minor OnnxProtoBuilder change
 - unused imports
 - Implementation of dedicated OnnxProtoBuilder
 - OnnxRuntime work in progress
 - OnnxRuntime work in progress
 - separated RuntimeTest
 - ONNX FFM Runtime initial work

Changes: https://git.openjdk.org/babylon/pull/311/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=311&range=00
  Stats: 936 lines in 7 files changed: 931 ins; 4 del; 1 mod
  Patch: https://git.openjdk.org/babylon/pull/311.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/311/head:pull/311

PR: https://git.openjdk.org/babylon/pull/311