[code-reflection] RFR: Initializers through arguments [v9]

[Adam Sotona]

> Initializers through arguments implementation.
> This PR is chained to ongoing work on `If` and `Loop` due to conflicting changes in `OnnxProtoBuilder`.
> 
> Input image reshape has to be removed from the CNN model due to unexpected exceptions in `Conv` op in relation with initializers.

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

  OnnxProtoBuilder and OnnxProtoPrinter implemented support for packed data

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Changes:
  - all: https://git.openjdk.org/babylon/pull/340/files
  - new: https://git.openjdk.org/babylon/pull/340/files/d885df19..5a0213f9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=340&range=08
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=340&range=07-08

  Stats: 135 lines in 2 files changed: 89 ins; 1 del; 45 mod
  Patch: https://git.openjdk.org/babylon/pull/340.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/340/head:pull/340

PR: https://git.openjdk.org/babylon/pull/340