[code-reflection] Integrated: Hat schema cleanup

[Gary Frost]

Removed duplicated code between ifacemapper and schema. 
Cleaned up Schema and BoundSchema.

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

Commit messages:
 - More schema cleanup
 - Schema cleanup and reuse MappingUtil
 - Schema differentiate between primitive nodes and ifacemapped nodes

Changes: https://git.openjdk.org/babylon/pull/178/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=178&range=00
  Stats: 795 lines in 22 files changed: 357 ins; 261 del; 177 mod
  Patch: https://git.openjdk.org/babylon/pull/178.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/178/head:pull/178

PR: https://git.openjdk.org/babylon/pull/178