[code-reflection] Integrated: Allow schema decoding from native code

[Gary Frost]

We pass a description of the args when we dispatch a kernel, this  `argsled` includes schema information about any iface mapped segments.  

This allows the backend to dump the memory in the segment for debugging purposes. So far we can decode the schema.

-------------

Commit messages:
 - Allow schema decoding from native code

Changes: https://git.openjdk.org/babylon/pull/123/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=123&range=00
  Stats: 659 lines in 4 files changed: 309 ins; 257 del; 93 mod
  Patch: https://git.openjdk.org/babylon/pull/123.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/123/head:pull/123

PR: https://git.openjdk.org/babylon/pull/123