[code-reflection] RFR: PTX backend implementation for HAT

[Ruby Chen]

Implemented a PTX backend for HAT kernel execution; PTX will run on machines with supporting Nvidia GPUs. Currently works for Squares and Mandel kernel examples.

Also starting to implement a BlackScholes kernel for HAT.

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Commit messages:
 - adding oracle headers
 - removed unused functions for ptx
 - added support for calling non-kernel functions
 - adding ptx conversion for non-kernel functions
 - cleaning up code
 - mandel works!
 - squares works!
 - testing mandel
 - cleaning up mandel ptx conversion
 - testing squares.java

Changes: https://git.openjdk.org/babylon/pull/188/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=188&range=00
  Stats: 1194 lines in 6 files changed: 1128 ins; 61 del; 5 mod
  Patch: https://git.openjdk.org/babylon/pull/188.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/188/head:pull/188

PR: https://git.openjdk.org/babylon/pull/188