[code-reflection] Integrated: Make it easier to create simple schemas

[Gary Frost]

An attempt to simplify the creation of simple schemas.  We may be able to extend this approach (skipping the builder) to other more complex schemas later.

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Commit messages:
 - Make it easier to create simple schemas

Changes: https://git.openjdk.org/babylon/pull/718/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=718&range=00
  Stats: 139 lines in 13 files changed: 56 ins; 54 del; 29 mod
  Patch: https://git.openjdk.org/babylon/pull/718.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/718/head:pull/718

PR: https://git.openjdk.org/babylon/pull/718