[code-reflection] Integrated: Fixed nbody state init issue. Split out ffi-shared java code as separate module.

[Gary Frost]

Fixed nbody state init issue.

* Nbody was not detecting buffers in 'NEW' state and was incorrectly assuming we had OpenCL buf bindings
    
Split out ffi-shared java code as separate module. Updated bld/run as…… necessary.

* This re-org balances the hat-core and ffi-backends dependencies. Now only ffi backends see infra for handing native backends

The move to allowing 'escaping' buffers to be minimized complete.   

* If buffer escapes 'compute' we treat it as if it were Read and Mutated.  Unless the 'reciever' annotates the recieving arg slot with @RO or @WO which will allow us to skip at least one copy.

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Commit messages:
 - Split out ffi-shared java code as separate module. Updated bld/run as necessary. Fixed nbody initial buffer state issue.

Changes: https://git.openjdk.org/babylon/pull/368/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=368&range=00
  Stats: 684 lines in 20 files changed: 302 ins; 271 del; 111 mod
  Patch: https://git.openjdk.org/babylon/pull/368.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/368/head:pull/368

PR: https://git.openjdk.org/babylon/pull/368