[code-reflection] RFR: ONNX FFM Runtime initial work [v11]

[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

Adam Sotona has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 20 commits:

 - Merge remote-tracking branch 'babylon/code-reflection' into onnx-runtime-initial
 - initial draft of OnnxProtoBuilder::buildFuncModel and OnnxRuntime::runFunc
   
 - OnnxProtoBuilder and OnnxRuntime simplifications
   
 - OnnxProtoBuilder resolution of output tensor types from scheme + shape fix and test
   
 - OnnxProtoBuilder and OnnxRuntime work in progress
   
 - working with flat tensors by default
   
 - runtime getting tensor element type from the first input value
   
 - interpreter returns array of tensors for multiple outputs
   
 - Merge remote-tracking branch 'babylon/code-reflection' into onnx-runtime-initial
   
 - Merged OnnxRuntime with OnnxRuntime.Environment and made singleton with shutdown hook
   
 - ... and 10 more: https://git.openjdk.org/babylon/compare/7ce041b3...f89647d7

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Changes: https://git.openjdk.org/babylon/pull/311/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=311&range=10
  Stats: 1106 lines in 8 files changed: 1100 ins; 4 del; 2 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