[code-reflection] Integrated: Re organized code builder hierarchy

[Gary Frost]

The HAT high level (C99) builders used by CUDA, OpenCL  and HIP  were a mess.  I removed one level of Builder (an abstract class with no methods).

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Commit messages:
 - Re organized code builder heirarchy
 - Re organized code builder heirarchy

Changes: https://git.openjdk.org/babylon/pull/303/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=303&range=00
  Stats: 1320 lines in 18 files changed: 591 ins; 671 del; 58 mod
  Patch: https://git.openjdk.org/babylon/pull/303.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/303/head:pull/303

PR: https://git.openjdk.org/babylon/pull/303