[code-reflection] Integrated: Cloned CUDA backend native code to PTX backend

[Gary Frost]

We will need native backend for testing PTX work.  It will be very close to the existing CUDA backend.

So at present we clone the CUDA one.

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Commit messages:
 - Cloned CUDA backend native code to PTX backend

Changes: https://git.openjdk.org/babylon/pull/140/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=140&range=00
  Stats: 681 lines in 6 files changed: 580 ins; 54 del; 47 mod
  Patch: https://git.openjdk.org/babylon/pull/140.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/140/head:pull/140

PR: https://git.openjdk.org/babylon/pull/140