[code-reflection] RFR: [hat] Reduces the number of threads in thread-block for small kernels

[Juan Fumero]

Reduces the number of threads in thread-block for small kernels.
This should be trigger only when debugging small kernels with the CUDA backend.

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Commit messages:
 - [hat] Reduces the number of threads in thread-block for small kernels

Changes: https://git.openjdk.org/babylon/pull/694/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=694&range=00
  Stats: 69 lines in 3 files changed: 46 ins; 18 del; 5 mod
  Patch: https://git.openjdk.org/babylon/pull/694.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/694/head:pull/694

PR: https://git.openjdk.org/babylon/pull/694