[code-reflection] Integrated: We were needlessly passing accelerator around, as a Lookup carrier

[Gary Frost]

We added LookupCarrier interface recently, but were still passing around Accelerator as a LookupCarrier. 

Now we can define buffers in optkl and use them from HAT. 

Also we were using accelerator as an allocator (ArenaCarrier/BufferBuilder) so now we separate those as well.

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Commit messages:
 - We were needlessly passing accelerator around, as a Lookup carrier, now we pass as a LookupCarrier

Changes: https://git.openjdk.org/babylon/pull/780/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=780&range=00
  Stats: 536 lines in 70 files changed: 61 ins; 228 del; 247 mod
  Patch: https://git.openjdk.org/babylon/pull/780.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/780/head:pull/780

PR: https://git.openjdk.org/babylon/pull/780