[code-reflection] Integrated: Moved the generation of random suffix for schema padding to codegen

[Gary Frost]

As I experiment with schema building.  I noticed some codegen code (random pading suffix) in the schema code itself.  

I moved this to the C99 code gen.

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Commit messages:
 - Moved the generation of random suffix for schema padding to codegen

Changes: https://git.openjdk.org/babylon/pull/763/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=763&range=00
  Stats: 44 lines in 2 files changed: 15 ins; 27 del; 2 mod
  Patch: https://git.openjdk.org/babylon/pull/763.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/763/head:pull/763

PR: https://git.openjdk.org/babylon/pull/763