[code-reflection] RFR: Added some NDRange helpers to simplify N dim ranges

[Gary Frost]

Creating multi dim NDRange's can be quite verbose.  I added some static helper methods simplify this. 

An example  for 2D range with global and local sizing was   

        NDRange ndRange = NDRange.of(NDRange.Global2D.of(256, 256), NDRange.Local2D.of(16, 16));
``` 
We can now use 

        NDRange ndRange = NDRange.of2D(256, 256,16, 16));

The prev version is still available, the later merely delegates to the former.

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Commit messages:
 - Added some NDRange helpers to simplify N dim ranges

Changes: https://git.openjdk.org/babylon/pull/698/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=698&range=00
  Stats: 56 lines in 5 files changed: 49 ins; 1 del; 6 mod
  Patch: https://git.openjdk.org/babylon/pull/698.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/698/head:pull/698

PR: https://git.openjdk.org/babylon/pull/698