[code-reflection] Integrated: Moved raster code from shade to experiments and de-dupped typedefs

[Gary Frost]

When moving code from shade example to experiments.  I noticed that we were generating multiple typedefs for the same iface type if a buffer contained multiple fields. 

So this PR has the code refactoring and a fix for de-duping the typedefs.

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

Commit messages:
 - Moved raster code from shade to experiments and de-dupped typedefs

Changes: https://git.openjdk.org/babylon/pull/893/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=893&range=00
  Stats: 553 lines in 17 files changed: 110 ins; 419 del; 24 mod
  Patch: https://git.openjdk.org/babylon/pull/893.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/893/head:pull/893

PR: https://git.openjdk.org/babylon/pull/893