[code-reflection] Integrated: Hat merge cuda opencl backend common code 1

[Gary Frost]

More progress moving opencl/cuda ffi specific code to ffi-shared

We still need to test and integrate the CUDA side.

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Commit messages:
 - Moved all kernel dispatch to ffi-shared, ready to refactor CUDA side now
 - Moving core/common backend functionality down to ffi-shared

Changes: https://git.openjdk.org/babylon/pull/388/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=388&range=00
  Stats: 1239 lines in 14 files changed: 493 ins; 440 del; 306 mod
  Patch: https://git.openjdk.org/babylon/pull/388.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/388/head:pull/388

PR: https://git.openjdk.org/babylon/pull/388