[code-reflection] RFR: [hat] mxm example with loop interchange

[Juan Fumero]

Improve Matrix Multiplication example with Loop Interchange. 
The example has been tested for the OpenCL backend. 

How to run? 


java @hat/run ffi-opencl matmul 2DLI

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Commit messages:
 - [hat] mxm example with loop interchange

Changes: https://git.openjdk.org/babylon/pull/500/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=500&range=00
  Stats: 45 lines in 2 files changed: 37 ins; 2 del; 6 mod
  Patch: https://git.openjdk.org/babylon/pull/500.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/500/head:pull/500

PR: https://git.openjdk.org/babylon/pull/500